diff --git a/core/modules/book/book.admin.inc b/core/modules/book/book.admin.inc
index 611537b..07ba878 100644
--- a/core/modules/book/book.admin.inc
+++ b/core/modules/book/book.admin.inc
@@ -79,11 +79,10 @@ function book_admin_edit_submit($form, &$form_state) {
       // Update the title if changed.
       if ($row['title']['#default_value'] != $values['title']) {
         $node = node_load($values['nid']);
-        $langcode = Language::LANGCODE_NOT_SPECIFIED;
         $node->title = $values['title'];
-        $node->book['link_title'] = $values['title'];
+        $node->book->link_title = $values['title'];
         $node->setNewRevision();
-        $node->log = t('Title changed from %original to %current.', array('%original' => $node->title, '%current' => $values['title']));
+        $node->log = t('Title changed from %original to %current.', array('%original' => $node->label(), '%current' => $values['title']));
 
         $node->save();
         watchdog('content', 'book: updated %title.', array('%title' => $node->label()), WATCHDOG_NOTICE, l(t('view'), 'node/' . $node->id()));
diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index 23dd8d7..ecf0db0 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -113,6 +113,21 @@ function book_permission() {
 }
 
 /**
+ * Implements hook_entity_field_info().
+ */
+function book_entity_field_info($entity_type) {
+  if ($entity_type === 'node') {
+    $info['definitions']['book'] = array(
+      'type' => 'book_field',
+      'label' => t('The book data'),
+      'computed' => TRUE,
+      'list' => TRUE,
+    );
+    return $info;
+  }
+}
+
+/**
  * Adds relevant book links to the node's links.
  *
  * @param \Drupal\Core\Entity\EntityInterface $node
@@ -123,14 +138,14 @@ function book_permission() {
 function book_node_view_link(NodeInterface $node, $view_mode) {
   $links = array();
 
-  if (isset($node->book['depth'])) {
+  if (isset($node->book->depth)) {
     if ($view_mode == 'full' && node_is_page($node)) {
       $child_type = config('book.settings')->get('child_type');
-      if ((user_access('add content to books') || user_access('administer book outlines')) && node_access('create', $child_type) && $node->isPublished() && $node->book['depth'] < MENU_MAX_DEPTH) {
+      if ((user_access('add content to books') || user_access('administer book outlines')) && node_access('create', $child_type) && $node->isPublished() && $node->book->depth < MENU_MAX_DEPTH) {
         $links['book_add_child'] = array(
           'title' => t('Add child page'),
           'href' => 'node/add/' . $child_type,
-          'query' => array('parent' => $node->book['mlid']),
+          'query' => array('parent' => $node->book->mlid),
         );
       }
 
@@ -265,7 +280,7 @@ function _book_outline_remove_access(EntityInterface $node) {
  *   The node to remove from the outline.
  */
 function _book_node_is_removable(EntityInterface $node) {
-  return (!empty($node->book['bid']) && (($node->book['bid'] != $node->id()) || !$node->book['has_children']));
+  return (!empty($node->book->bid) && (($node->book->bid != $node->id()) || !$node->book->has_children));
 }
 
 /**
@@ -307,7 +322,7 @@ function book_form_node_form_alter(&$form, &$form_state, $form_id) {
   $node = $form_state['controller']->getEntity();
   $access = user_access('administer book outlines');
   if (!$access) {
-    if (user_access('add content to books') && ((!empty($node->book['mlid']) && !$node->isNew()) || book_type_is_allowed($node->bundle()))) {
+    if (user_access('add content to books') && ((!empty($node->book->mlid) && !$node->isNew()) || book_type_is_allowed($node->bundle()))) {
       // Already in the book hierarchy, or this node type is allowed.
       $access = TRUE;
     }
@@ -373,25 +388,25 @@ function _book_parent_select($book_link) {
     '#suffix' => '</div>',
   );
 
-  if ($book_link['nid'] === $book_link['bid']) {
+  if ($book_link->nid === $book_link->bid) {
     // This is a book - at the top level.
-    if ($book_link['original_bid'] === $book_link['bid']) {
+    if ($book_link->original_bid === $book_link->bid) {
       $form['#prefix'] .= '<em>' . t('This is the top-level page in this book.') . '</em>';
     }
     else {
       $form['#prefix'] .= '<em>' . t('This will be the top-level page in this book.') . '</em>';
     }
   }
-  elseif (!$book_link['bid']) {
+  elseif (!$book_link->bid) {
     $form['#prefix'] .= '<em>' . t('No book selected.') . '</em>';
   }
   else {
     $form = array(
       '#type' => 'select',
       '#title' => t('Parent item'),
-      '#default_value' => $book_link['plid'],
+      '#default_value' => $book_link->plid,
       '#description' => t('The parent page in the book. The maximum depth for a book and all child pages is !maxdepth. Some pages in the selected book may not be available as parents if selecting them would exceed this limit.', array('!maxdepth' => MENU_MAX_DEPTH)),
-      '#options' => book_toc($book_link['bid'], $book_link['parent_depth_limit'], array($book_link['mlid'])),
+      '#options' => book_toc($book_link->bid, $book_link->parent_depth_limit, array($book_link->mlid)),
       '#attributes' => array('class' => array('book-title-select')),
       '#prefix' => '<div id="edit-book-plid-wrapper">',
       '#suffix' => '</div>',
@@ -431,7 +446,7 @@ function _book_add_form_elements(&$form, &$form_state, EntityInterface $node) {
   foreach (array('menu_name', 'mlid', 'nid', 'router_path', 'has_children', 'options', 'module', 'original_bid', 'parent_depth_limit') as $key) {
     $form['book'][$key] = array(
       '#type' => 'value',
-      '#value' => $node->book[$key],
+      '#value' => $node->book->$key,
     );
   }
 
@@ -441,15 +456,15 @@ function _book_add_form_elements(&$form, &$form_state, EntityInterface $node) {
   $form['book']['weight'] = array(
     '#type' => 'weight',
     '#title' => t('Weight'),
-    '#default_value' => $node->book['weight'],
-    '#delta' => max(15, abs($node->book['weight'])),
+    '#default_value' => $node->book->weight,
+    '#delta' => max(15, abs($node->book->weight)),
     '#weight' => 5,
     '#description' => t('Pages at a given level are ordered first by weight and then by title.'),
   );
   $options = array();
   $nid = !$node->isNew() ? $node->id() : 'new';
 
-  if ($node->id() && ($nid == $node->book['original_bid']) && ($node->book['parent_depth_limit'] == 0)) {
+  if ($node->id() && ($nid == $node->book->original_bid) && ($node->book->parent_depth_limit == 0)) {
     // This is the top level node in a maximum depth book and thus cannot be moved.
     $options[$node->id()] = $node->label();
   }
@@ -459,11 +474,11 @@ function _book_add_form_elements(&$form, &$form_state, EntityInterface $node) {
     }
   }
 
-  if (user_access('create new books') && ($nid == 'new' || ($nid != $node->book['original_bid']))) {
+  if (user_access('create new books') && ($nid == 'new' || ($nid != $node->book->original_bid))) {
     // The node can become a new book, if it is not one already.
     $options = array($nid => t('- Create a new book -')) + $options;
   }
-  if (!$node->book['mlid']) {
+  if (!$node->book->mlid) {
     // The node is not currently in the hierarchy.
     $options = array(0 => t('- None -')) + $options;
   }
@@ -472,7 +487,7 @@ function _book_add_form_elements(&$form, &$form_state, EntityInterface $node) {
   $form['book']['bid'] = array(
     '#type' => 'select',
     '#title' => t('Book'),
-    '#default_value' => $node->book['bid'],
+    '#default_value' => $node->book->bid,
     '#options' => $options,
     '#access' => (bool) $options,
     '#description' => t('Your page will be a part of the selected book.'),
@@ -514,50 +529,52 @@ function book_form_update($form, $form_state) {
  *   TRUE if the menu link was saved; FALSE otherwise.
  */
 function _book_update_outline(EntityInterface $node) {
-  if (empty($node->book['bid'])) {
+  if (empty($node->book->bid)) {
     return FALSE;
   }
-  $new = empty($node->book['mlid']);
+  $new = empty($node->book->mlid);
 
-  $node->book['link_path'] = 'node/' . $node->id();
-  $node->book['link_title'] = $node->label();
-  $node->book['parent_mismatch'] = FALSE; // The normal case.
+  $node->book->link_path = 'node/' . $node->id();
+  $node->book->link_title = $node->label();
+  $node->book->parent_mismatch = FALSE; // The normal case.
 
-  if ($node->book['bid'] == $node->id()) {
-    $node->book['plid'] = 0;
-    $node->book['menu_name'] = book_menu_name($node->id());
+  if ($node->book->bid == $node->id()) {
+    $node->book->plid = 0;
+    $node->book->menu_name = book_menu_name($node->id());
   }
   else {
     // Check in case the parent is not is this book; the book takes precedence.
-    if (!empty($node->book['plid'])) {
+    if (!empty($node->book->plid)) {
       $parent = db_query("SELECT * FROM {book} WHERE mlid = :mlid", array(
-        ':mlid' => $node->book['plid'],
+        ':mlid' => $node->book->plid,
       ))->fetchAssoc();
     }
-    if (empty($node->book['plid']) || !$parent || $parent['bid'] != $node->book['bid']) {
-      $node->book['plid'] = db_query("SELECT mlid FROM {book} WHERE nid = :nid", array(
-        ':nid' => $node->book['bid'],
+    if (empty($node->book->plid) || !$parent || $parent['bid'] != $node->book->bid) {
+      $node->book->plid = db_query("SELECT mlid FROM {book} WHERE nid = :nid", array(
+        ':nid' => $node->book->bid,
       ))->fetchField();
-      $node->book['parent_mismatch'] = TRUE; // Likely when JS is disabled.
+      $node->book->parent_mismatch = TRUE; // Likely when JS is disabled.
     }
   }
 
-  $node->book = entity_create('menu_link', $node->book);
-  if ($node->book->save()) {
+  $link = entity_create('menu_link', $node->book->getValue());
+  debug($link);
+  if ($link->save()) {
+    debug($link);
     if ($new) {
       // Insert new.
       db_insert('book')
         ->fields(array(
           'nid' => $node->id(),
-          'mlid' => $node->book['mlid'],
-          'bid' => $node->book['bid'],
+          'mlid' => $link->mlid,
+          'bid' => $node->book->bid,
         ))
         ->execute();
       // Reset the cache of stored books.
       drupal_static_reset('book_get_books');
     }
     else {
-      if ($node->book['bid'] != db_query("SELECT bid FROM {book} WHERE nid = :nid", array(
+      if ($node->book->bid != db_query("SELECT bid FROM {book} WHERE nid = :nid", array(
           ':nid' => $node->id(),
         ))->fetchField()) {
         // Update the bid for this page and all children.
@@ -583,14 +600,14 @@ function _book_update_outline(EntityInterface $node) {
 function book_update_bid($book_link) {
   $query = db_select('menu_links');
   $query->addField('menu_links', 'mlid');
-  for ($i = 1; $i <= MENU_MAX_DEPTH && $book_link["p$i"]; $i++) {
-    $query->condition("p$i", $book_link["p$i"]);
+  for ($i = 1; $i <= MENU_MAX_DEPTH && $book_link->{"p$i"}; $i++) {
+    $query->condition("p$i", $book_link->{"p$i"});
   }
   $mlids = $query->execute()->fetchCol();
 
   if ($mlids) {
     db_update('book')
-      ->fields(array('bid' => $book_link['bid']))
+      ->fields(array('bid' => $book_link->bid))
       ->condition('mlid', $mlids, 'IN')
       ->execute();
   }
@@ -612,14 +629,14 @@ function book_update_bid($book_link) {
 function book_get_flat_menu($book_link) {
   $flat = &drupal_static(__FUNCTION__, array());
 
-  if (!isset($flat[$book_link['mlid']])) {
+  if (!isset($flat[$book_link->mlid])) {
     // Call menu_tree_all_data() to take advantage of the menu system's caching.
-    $tree = menu_tree_all_data($book_link['menu_name'], $book_link, $book_link['depth'] + 1);
-    $flat[$book_link['mlid']] = array();
-    _book_flatten_menu($tree, $flat[$book_link['mlid']]);
+    $tree = menu_tree_all_data($book_link->menu_name, $book_link, $book_link->depth + 1);
+    $flat[$book_link->mlid] = array();
+    _book_flatten_menu($tree, $flat[$book_link->mlid]);
   }
 
-  return $flat[$book_link['mlid']];
+  return $flat[$book_link->mlid];
 }
 
 /**
@@ -655,7 +672,7 @@ function _book_flatten_menu($tree, &$flat) {
  */
 function book_prev($book_link) {
   // If the parent is zero, we are at the start of a book.
-  if ($book_link['plid'] == 0) {
+  if ($book_link->plid == 0) {
     return NULL;
   }
   $flat = book_get_flat_menu($book_link);
@@ -664,11 +681,11 @@ function book_prev($book_link) {
   do {
     $prev = $curr;
     list($key, $curr) = each($flat);
-  } while ($key && $key != $book_link['mlid']);
+  } while ($key && $key != $book_link->mlid);
 
-  if ($key == $book_link['mlid']) {
+  if ($key == $book_link->mlid) {
     // The previous page in the book may be a child of the previous visible link.
-    if ($prev['depth'] == $book_link['depth'] && $prev['has_children']) {
+    if ($prev->depth == $book_link->depth && $prev->has_children) {
       // The subtree will have only one link at the top level - get its data.
       $tree = book_menu_subtree_data($prev);
       $data = array_shift($tree);
@@ -701,9 +718,9 @@ function book_next($book_link) {
   do {
     list($key, $curr) = each($flat);
   }
-  while ($key && $key != $book_link['mlid']);
+  while ($key && $key != $book_link->mlid);
 
-  if ($key == $book_link['mlid']) {
+  if ($key == $book_link->mlid) {
     return current($flat);
   }
 }
@@ -722,14 +739,14 @@ function book_children($book_link) {
 
   $children = array();
 
-  if ($book_link['has_children']) {
+  if ($book_link->has_children) {
     // Walk through the array until we find the current page.
     do {
       $link = array_shift($flat);
     }
-    while ($link && ($link['mlid'] != $book_link['mlid']));
+    while ($link && ($link['mlid'] != $book_link->mlid));
     // Continue though the array and collect the links whose parent is this page.
-    while (($link = array_shift($flat)) && $link['plid'] == $book_link['mlid']) {
+    while (($link = array_shift($flat)) && $link['plid'] == $book_link->mlid) {
       $data['link'] = $link;
       $data['below'] = '';
       $children[] = $data;
@@ -762,10 +779,11 @@ function book_menu_name($bid) {
 function book_node_load($nodes, $types) {
   $result = db_query("SELECT * FROM {book} b INNER JOIN {menu_links} ml ON b.mlid = ml.mlid WHERE b.nid IN (:nids)", array(':nids' =>  array_keys($nodes)), array('fetch' => PDO::FETCH_ASSOC));
   foreach ($result as $record) {
+    debug($record);
     $nodes[$record['nid']]->book = $record;
-    $nodes[$record['nid']]->book['href'] = $record['link_path'];
-    $nodes[$record['nid']]->book['title'] = $record['link_title'];
-    $nodes[$record['nid']]->book['options'] = unserialize($record['options']);
+    $nodes[$record['nid']]->book->href = $record['link_path'];
+    $nodes[$record['nid']]->book->title = $record['link_title'];
+    $nodes[$record['nid']]->book->options = unserialize($record['options']);
   }
 }
 
@@ -774,7 +792,7 @@ function book_node_load($nodes, $types) {
  */
 function book_node_view(EntityInterface $node, EntityDisplay $display, $view_mode) {
   if ($view_mode == 'full') {
-    if (!empty($node->book['bid']) && empty($node->in_preview)) {
+    if (!empty($node->book->bid) && empty($node->in_preview)) {
       $book_navigation = array( '#theme' => 'book_navigation', '#book_link' => $node->book);
       $node->content['book_navigation'] = array(
         '#markup' => drupal_render($book_navigation),
@@ -800,9 +818,9 @@ function book_node_view(EntityInterface $node, EntityDisplay $display, $view_mod
  * viewing a book page.
  */
 function book_page_alter(&$page) {
-  if (($node = menu_get_object()) && !empty($node->book['bid'])) {
+  if (($node = menu_get_object()) && !empty($node->book->bid)) {
     $active_menus = menu_get_active_menu_names();
-    $active_menus[] = $node->book['menu_name'];
+    $active_menus[] = $node->book->menu_name;
     menu_set_active_menu_names($active_menus);
   }
 }
@@ -812,12 +830,12 @@ function book_page_alter(&$page) {
  */
 function book_node_presave(EntityInterface $node) {
   // Always save a revision for non-administrators.
-  if (!empty($node->book['bid']) && !user_access('administer nodes')) {
+  if (!empty($node->book->bid) && !user_access('administer nodes')) {
     $node->setNewRevision();
   }
   // Make sure a new node gets a new menu link.
   if ($node->isNew()) {
-    $node->book['mlid'] = NULL;
+    $node->book->mlid = NULL;
   }
 }
 
@@ -825,13 +843,13 @@ function book_node_presave(EntityInterface $node) {
  * Implements hook_node_insert().
  */
 function book_node_insert(EntityInterface $node) {
-  if (!empty($node->book['bid'])) {
-    if ($node->book['bid'] == 'new') {
+  if (!empty($node->book->bid)) {
+    if ($node->book->bid == 'new') {
       // New nodes that are their own book.
-      $node->book['bid'] = $node->id();
+      $node->book->bid = $node->id();
     }
-    $node->book['nid'] = $node->id();
-    $node->book['menu_name'] = book_menu_name($node->book['bid']);
+    $node->book->nid = $node->id();
+    $node->book->menu_name = book_menu_name($node->book->bid);
     _book_update_outline($node);
   }
 }
@@ -840,13 +858,13 @@ function book_node_insert(EntityInterface $node) {
  * Implements hook_node_update().
  */
 function book_node_update(EntityInterface $node) {
-  if (!empty($node->book['bid'])) {
-    if ($node->book['bid'] == 'new') {
+  if (!empty($node->book->bid)) {
+    if ($node->book->bid == 'new') {
       // New nodes that are their own book.
-      $node->book['bid'] = $node->id();
+      $node->book->bid = $node->id();
     }
-    $node->book['nid'] = $node->id();
-    $node->book['menu_name'] = book_menu_name($node->book['bid']);
+    $node->book->nid = $node->id();
+    $node->book->menu_name = book_menu_name($node->book->bid);
     _book_update_outline($node);
   }
 }
@@ -855,21 +873,21 @@ function book_node_update(EntityInterface $node) {
  * Implements hook_node_predelete().
  */
 function book_node_predelete(EntityInterface $node) {
-  if (!empty($node->book['bid'])) {
-    if ($node->id() == $node->book['bid']) {
+  if (!empty($node->book->bid)) {
+    if ($node->id() == $node->book->bid) {
       // Handle deletion of a top-level post.
       $result = db_query("SELECT b.nid FROM {menu_links} ml INNER JOIN {book} b on b.mlid = ml.mlid WHERE ml.plid = :plid", array(
-        ':plid' => $node->book['mlid']
+        ':plid' => $node->book->mlid
       ));
       foreach ($result as $child) {
         $child_node = node_load($child->id());
-        $child_node->book['bid'] = $child_node->id();
+        $child_node->book->bid = $child_node->id();
         _book_update_outline($child_node);
       }
     }
-    menu_link_delete($node->book['mlid']);
+    menu_link_delete($node->book->mlid);
     db_delete('book')
-      ->condition('mlid', $node->book['mlid'])
+      ->condition('mlid', $node->book->mlid)
       ->execute();
     drupal_static_reset('book_get_books');
   }
@@ -889,22 +907,22 @@ function book_node_prepare_form(NodeInterface $node, $form_display, $operation,
       $parent = book_link_load($query->get('parent'));
 
       if ($parent && $parent['access']) {
-        $node->book['bid'] = $parent['bid'];
-        $node->book['plid'] = $parent['mlid'];
-        $node->book['menu_name'] = $parent['menu_name'];
+        $node->book->bid = $parent['bid'];
+        $node->book->plid = $parent['mlid'];
+        $node->book->menu_name = $parent['menu_name'];
       }
     }
     // Set defaults.
     $node->book += _book_link_defaults(!$node->isNew() ? $node->id() : 'new');
   }
   else {
-    if (isset($node->book['bid']) && !isset($node->book['original_bid'])) {
-      $node->book['original_bid'] = $node->book['bid'];
+    if (isset($node->book->bid) && !isset($node->book->original_bid)) {
+      $node->book->original_bid = $node->book->bid;
     }
   }
   // Find the depth limit for the parent select.
-  if (isset($node->book['bid']) && !isset($node->book['parent_depth_limit'])) {
-    $node->book['parent_depth_limit'] = _book_parent_depth_limit($node->book);
+  if (isset($node->book->bid) && !isset($node->book->parent_depth_limit)) {
+    $node->book->parent_depth_limit = _book_parent_depth_limit($node->book);
   }
 }
 
@@ -918,7 +936,7 @@ function book_node_prepare_form(NodeInterface $node, $form_display, $operation,
  *   The depth limit for items in the parent select.
  */
 function _book_parent_depth_limit($book_link) {
-  return MENU_MAX_DEPTH - 1 - (($book_link['mlid'] && $book_link['has_children']) ? entity_get_controller('menu_link')->findChildrenRelativeDepth($book_link) : 0);
+  return MENU_MAX_DEPTH - 1 - (($book_link->mlid && $book_link->has_children) ? entity_get_controller('menu_link')->findChildrenRelativeDepth($book_link) : 0);
 }
 
 /**
@@ -931,7 +949,7 @@ function _book_parent_depth_limit($book_link) {
 function book_form_node_delete_confirm_alter(&$form, $form_state) {
   $node = node_load($form['nid']['#value']);
 
-  if (isset($node->book) && $node->book['has_children']) {
+  if (isset($node->book) && $node->book->has_children) {
     $form['book_warning'] = array(
       '#markup' => '<p>' . t('%title is part of a book outline, and has associated child pages. If you proceed with deletion, the child pages will be relocated automatically.', array('%title' => $node->label())) . '</p>',
       '#weight' => -10,
@@ -998,13 +1016,13 @@ function template_preprocess_book_navigation(&$variables) {
   $book_link = $variables['book_link'];
 
   // Provide extra variables for themers. Not needed by default.
-  $variables['book_id'] = $book_link['bid'];
-  $variables['book_title'] = check_plain($book_link['link_title']);
-  $variables['book_url'] = 'node/' . $book_link['bid'];
-  $variables['current_depth'] = $book_link['depth'];
+  $variables['book_id'] = $book_link->bid;
+  $variables['book_title'] = check_plain($book_link->link_title);
+  $variables['book_url'] = 'node/' . $book_link->bid;
+  $variables['current_depth'] = $book_link->depth;
   $variables['tree'] = '';
 
-  if ($book_link['mlid']) {
+  if ($book_link->mlid) {
     $variables['tree'] = book_children($book_link);
 
     if ($prev = book_prev($book_link)) {
@@ -1014,7 +1032,7 @@ function template_preprocess_book_navigation(&$variables) {
       $variables['prev_title'] = check_plain($prev['title']);
     }
 
-    if ($book_link['plid'] && $parent = book_link_load($book_link['plid'])) {
+    if ($book_link->plid && $parent = book_link_load($book_link->plid)) {
       $parent_href = url($parent['link_path']);
       drupal_add_html_head_link(array('rel' => 'up', 'href' => $parent_href));
       $variables['parent_url'] = $parent_href;
@@ -1099,7 +1117,9 @@ function _book_toc_recurse($tree, $indent, &$toc, $exclude, $depth_limit) {
  *   book page.
  */
 function book_toc($bid, $depth_limit, $exclude = array()) {
+  debug(array_keys(entity_load_multiple('menu')));
   $tree = menu_tree_all_data(book_menu_name($bid));
+  debug($tree);
   $toc = array();
   _book_toc_recurse($tree, '', $toc, $exclude, $depth_limit);
 
@@ -1208,7 +1228,7 @@ function book_node_export(EntityInterface $node, $children = '') {
  *     to an empty string.
  */
 function template_preprocess_book_node_export_html(&$variables) {
-  $variables['depth'] = $variables['node']->book['depth'];
+  $variables['depth'] = $variables['node']->book->depth;
   $variables['title'] = check_plain($variables['node']->label());
   $variables['content'] = $variables['node']->rendered;
 }
@@ -1290,7 +1310,7 @@ function book_menu_subtree_data($link) {
   $tree = &drupal_static(__FUNCTION__, array());
 
   // Generate a cache ID (cid) specific for this $menu_name and $link.
-  $cid = 'links:' . $link['menu_name'] . ':subtree-cid:' . $link['mlid'];
+  $cid = 'links:' . $link->menu_name . ':subtree-cid:' . $link->mlid;
 
   if (!isset($tree[$cid])) {
     $cache = cache('menu')->get($cid);
@@ -1313,22 +1333,24 @@ function book_menu_subtree_data($link) {
       $query->fields('b');
       $query->fields('m', array('load_functions', 'to_arg_functions', 'access_callback', 'access_arguments', 'page_callback', 'page_arguments', 'title', 'title_callback', 'title_arguments', 'type'));
       $query->fields('ml');
-      $query->condition('menu_name', $link['menu_name']);
-      for ($i = 1; $i <= MENU_MAX_DEPTH && $link["p$i"]; ++$i) {
-        $query->condition("p$i", $link["p$i"]);
+      $query->condition('menu_name', $link->menu_name);
+      for ($i = 1; $i <= MENU_MAX_DEPTH && $link->{"p$i"}; ++$i) {
+        $query->condition("p$i", $link->{"p$i"});
       }
       for ($i = 1; $i <= MENU_MAX_DEPTH; ++$i) {
         $query->orderBy("p$i");
       }
       $links = array();
+      debug((string)$query);
+      debug($query->getArguments());
       foreach ($query->execute() as $item) {
         $links[] = $item;
       }
-      $data['tree'] = menu_tree_data($links, array(), $link['depth']);
+      $data['tree'] = menu_tree_data($links, array(), $link->depth);
       $data['node_links'] = array();
       menu_tree_collect_node_links($data['tree'], $data['node_links']);
       // Compute the real cid for book subtree data.
-      $tree_cid = 'links:' . $item['menu_name'] . ':subtree-data:' . hash('sha256', serialize($data));
+      $tree_cid = 'links:' . $item->menu_name . ':subtree-data:' . hash('sha256', serialize($data));
       // Cache the data, if it is not already in the cache.
 
       if (!cache('menu')->get($tree_cid)) {
diff --git a/core/modules/book/book.pages.inc b/core/modules/book/book.pages.inc
index 4cd7e25..7b087f6 100644
--- a/core/modules/book/book.pages.inc
+++ b/core/modules/book/book.pages.inc
@@ -72,7 +72,7 @@ function book_export_html(EntityInterface $node) {
     if (isset($node->book)) {
       $tree = book_menu_subtree_data($node->book);
       $contents = book_export_traverse($tree, 'book_node_export');
-      $book_exported_html = array('#theme' => 'book_export_html', '#title' => $node->label(), '#contents' => $contents, '#depth' => $node->book['depth']);
+      $book_exported_html = array('#theme' => 'book_export_html', '#title' => $node->label(), '#contents' => $contents, '#depth' => $node->book->depth);
       return drupal_render($book_exported_html);
     }
     else {
@@ -118,12 +118,12 @@ function book_outline_form($form, &$form_state, EntityInterface $node) {
     $node->book = _book_link_defaults($node->id());
   }
   else {
-    $node->book['original_bid'] = $node->book['bid'];
+    $node->book->original_bid = $node->book->bid;
   }
 
   // Find the depth limit for the parent select.
-  if (!isset($node->book['parent_depth_limit'])) {
-    $node->book['parent_depth_limit'] = _book_parent_depth_limit($node->book);
+  if (!isset($node->book->parent_depth_limit)) {
+    $node->book->parent_depth_limit = _book_parent_depth_limit($node->book);
   }
   $form['#node'] = $node;
   $form['#id'] = 'book-outline';
@@ -131,7 +131,7 @@ function book_outline_form($form, &$form_state, EntityInterface $node) {
 
   $form['update'] = array(
     '#type' => 'submit',
-    '#value' => $node->book['original_bid'] ? t('Update book outline') : t('Add to book outline'),
+    '#value' => $node->book->original_bid ? t('Update book outline') : t('Add to book outline'),
     '#weight' => 15,
   );
 
@@ -175,7 +175,7 @@ function book_outline_form_submit($form, &$form_state) {
   $book_link['menu_name'] = book_menu_name($book_link['bid']);
   $node->book = $book_link;
   if (_book_update_outline($node)) {
-    if ($node->book['parent_mismatch']) {
+    if ($node->book->parent_mismatch) {
       // This will usually only happen when JS is disabled.
       drupal_set_message(t('The post has been added to the selected book. You may now position it relative to other pages.'));
       $form_state['redirect'] = "node/" . $node->id() . "/outline";
@@ -203,7 +203,7 @@ function book_remove_form($form, &$form_state, EntityInterface $node) {
   $form['#node'] = $node;
   $title = array('%title' => $node->label());
 
-  if ($node->book['has_children']) {
+  if ($node->book->has_children) {
     $description = t('%title has associated child pages, which will be relocated automatically to maintain their connection to the book. To recreate the hierarchy (as it was before removing this page), %title may be added again using the Outline tab, and each of its former child pages will need to be relocated manually.', $title);
   }
   else {
@@ -219,7 +219,7 @@ function book_remove_form($form, &$form_state, EntityInterface $node) {
 function book_remove_form_submit($form, &$form_state) {
   $node = $form['#node'];
   if (_book_node_is_removable($node)) {
-    menu_link_delete($node->book['mlid']);
+    menu_link_delete($node->book->mlid);
     db_delete('book')
       ->condition('nid', $node->id())
       ->execute();
diff --git a/core/modules/book/lib/Drupal/book/Plugin/Block/BookNavigationBlock.php b/core/modules/book/lib/Drupal/book/Plugin/Block/BookNavigationBlock.php
index 8cacc04..fe7fd35 100644
--- a/core/modules/book/lib/Drupal/book/Plugin/Block/BookNavigationBlock.php
+++ b/core/modules/book/lib/Drupal/book/Plugin/Block/BookNavigationBlock.php
@@ -64,7 +64,7 @@ public function blockSubmit($form, &$form_state) {
   public function build() {
     $current_bid = 0;
     if ($node = menu_get_object()) {
-      $current_bid = empty($node->book['bid']) ? 0 : $node->book['bid'];
+      $current_bid = $node->book->bid;
     }
     if ($this->configuration['block_mode'] == 'all pages') {
       $book_menus = array();
@@ -73,7 +73,7 @@ public function build() {
         if ($book['bid'] == $current_bid) {
           // If the current page is a node associated with a book, the menu
           // needs to be retrieved.
-          $book_menus[$book_id] = menu_tree_output(menu_tree_all_data($node->book['menu_name'], $node->book));
+          $book_menus[$book_id] = menu_tree_output(menu_tree_all_data($node->book->menu_name, $node->book));
         }
         else {
           // Since we know we will only display a link to the top node, there
@@ -97,7 +97,7 @@ public function build() {
       // Only display this block when the user is browsing a book.
       $select = db_select('node', 'n')
         ->fields('n', array('nid'))
-        ->condition('n.nid', $node->book['bid'])
+        ->condition('n.nid', $node->book->bid)
         ->addTag('node_access');
       $nid = $select->execute()->fetchField();
       // Only show the block if the user has view access for the top-level node.
diff --git a/core/modules/book/lib/Drupal/book/Plugin/DataType/BookItem.php b/core/modules/book/lib/Drupal/book/Plugin/DataType/BookItem.php
new file mode 100644
index 0000000..c54822b
--- /dev/null
+++ b/core/modules/book/lib/Drupal/book/Plugin/DataType/BookItem.php
@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\book\Plugin\DataType\BookItem.
+ */
+
+namespace Drupal\book\Plugin\DataType;
+
+use Drupal\Core\TypedData\Annotation\DataType;
+use Drupal\Core\Annotation\Translation;
+use Drupal\Core\Entity\Field\FieldItemBase;
+
+/**
+ * Defines the 'book_field' entity field item.
+ *
+ * @DataType(
+ *   id = "book_field",
+ *   label = @Translation("Book field item"),
+ *   description = @Translation("An entity field containing a book id and related data."),
+ *   list_class = "\Drupal\Core\Entity\Field\Field"
+ * )
+ */
+class BookItem extends FieldItemBase {
+
+  /**
+   * Definitions of the contained properties.
+   *
+   * @see BookItem::getPropertyDefinitions()
+   *
+   * @var array
+   */
+  static $propertyDefinitions;
+
+  /**
+   * Implements \Drupal\Core\TypedData\ComplexDataInterface::getPropertyDefinitions().
+   */
+  public function getPropertyDefinitions() {
+    if (!isset(static::$propertyDefinitions)) {
+      static::$propertyDefinitions['bid'] = array(
+        'type' => 'integer',
+        'label' => t('Book id'),
+      );
+      static::$propertyDefinitions['menu_name'] = array(
+        'type' => 'string',
+        'label' => t('Menu name'),
+      );
+      static::$propertyDefinitions['link_path'] = array(
+        'type' => 'string',
+        'label' => t('Link path'),
+      );
+      static::$propertyDefinitions['link_title'] = array(
+        'type' => 'string',
+        'label' => t('Link title'),
+      );
+    }
+    return static::$propertyDefinitions;
+  }
+
+}
diff --git a/core/modules/book/lib/Drupal/book/Tests/BookTest.php b/core/modules/book/lib/Drupal/book/Tests/BookTest.php
index a72b92c..8caaa7c 100644
--- a/core/modules/book/lib/Drupal/book/Tests/BookTest.php
+++ b/core/modules/book/lib/Drupal/book/Tests/BookTest.php
@@ -80,6 +80,8 @@ function createBook() {
 
     $this->book = $this->createBookNode('new');
     $book = $this->book;
+    debug($book->id());
+    debug($book->getPropertyValues());
 
     /*
      * Add page hierarchy to book.
@@ -92,8 +94,11 @@ function createBook() {
      */
     $nodes = array();
     $nodes[] = $this->createBookNode($book->id()); // Node 0.
-    $nodes[] = $this->createBookNode($book->id(), $nodes[0]->book['mlid']); // Node 1.
-    $nodes[] = $this->createBookNode($book->id(), $nodes[0]->book['mlid']); // Node 2.
+    debug(1);
+    $nodes[] = $this->createBookNode($book->id(), $nodes[0]->book->mlid); // Node 1.
+    debug(2);
+    $nodes[] = $this->createBookNode($book->id(), $nodes[0]->book->mlid); // Node 2.
+    debug($nodes[0]->book->getValue());
     $nodes[] = $this->createBookNode($book->id()); // Node 3.
     $nodes[] = $this->createBookNode($book->id()); // Node 4.
 
@@ -494,7 +499,7 @@ public function testBookOrdering() {
     $this->drupalLogin($this->admin_user);
     $node1 = $this->createBookNode($book->id());
     $node2 = $this->createBookNode($book->id());
-    $plid = $node1->book['mlid'];
+    $plid = $node1->book->mlid;
 
     // Head to admin screen and attempt to re-order.
     $this->drupalGet('admin/structure/book/' . $book->id());
diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index a8ffc3d..d9e2d2f 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -278,17 +278,18 @@ function forum_node_validate(EntityInterface $node, $form) {
   if (_forum_node_check_node_type($node)) {
     $langcode = $form['taxonomy_forums']['#language'];
     // vocabulary is selected, not a "container" term.
-    if (!empty($node->taxonomy_forums[$langcode])) {
+    if (!$node->taxonomy_forums->isEmpty()) {
       // Extract the node's proper topic ID.
       $containers = config('forum.settings')->get('containers');
-      foreach ($node->taxonomy_forums[$langcode] as $delta => $item) {
+      foreach ($node->taxonomy_forums as $delta => $item) {
         // If no term was selected (e.g. when no terms exist yet), remove the
         // item.
-        if (empty($item['target_id'])) {
-          unset($node->taxonomy_forums[$langcode][$delta]);
+        if (empty($item->target_id)) {
+          // @todo: Does this work?
+          unset($node->taxonomy_forums[$delta]);
           continue;
         }
-        $term = entity_load('taxonomy_term', $item['target_id']);
+        $term = $item->entity;
         if (!$term) {
           form_set_error('taxonomy_forums', t('Select a forum.'));
           continue;
@@ -311,19 +312,18 @@ function forum_node_validate(EntityInterface $node, $form) {
  * Assigns the forum taxonomy when adding a topic from within a forum.
  */
 function forum_node_presave(EntityInterface $node) {
+
   if (_forum_node_check_node_type($node)) {
     // Make sure all fields are set properly:
     $node->icon = !empty($node->icon) ? $node->icon : '';
-    reset($node->taxonomy_forums);
-    $langcode = key($node->taxonomy_forums);
-    if (!empty($node->taxonomy_forums[$langcode])) {
-      $node->forum_tid = $node->taxonomy_forums[$langcode][0]['target_id'];
+    if (!$node->taxonomy_forums->isEmpty()) {
+      $node->forum_tid = $node->taxonomy_forums->target_id;
       // Only do a shadow copy check if this is not a new node.
       if (!$node->isNew()) {
         $old_tid = db_query_range("SELECT f.tid FROM {forum} f INNER JOIN {node} n ON f.vid = n.vid WHERE n.nid = :nid ORDER BY f.vid DESC", 0, 1, array(':nid' => $node->id()))->fetchField();
         if ($old_tid && isset($node->forum_tid) && ($node->forum_tid != $old_tid) && !empty($node->shadow)) {
           // A shadow copy needs to be created. Retain new term and add old term.
-          $node->taxonomy_forums[$langcode][] = array('target_id' => $old_tid);
+          $node->taxonomy_forums[count($node->taxonomy_forums)] = array('target_id' => $old_tid);
         }
       }
     }
@@ -501,6 +501,7 @@ function forum_comment_delete($comment) {
  * Implements hook_field_storage_pre_insert().
  */
 function forum_field_storage_pre_insert(EntityInterface $entity, &$skip_fields) {
+  $entity = $entity->getNGEntity();
   if ($entity->entityType() == 'node' && $entity->isPublished() && _forum_node_check_node_type($entity)) {
     $query = db_insert('forum_index')->fields(array('nid', 'title', 'tid', 'sticky', 'created', 'comment_count', 'last_comment_timestamp'));
     foreach ($entity->getTranslationLanguages() as $langcode => $language) {
@@ -525,6 +526,7 @@ function forum_field_storage_pre_insert(EntityInterface $entity, &$skip_fields)
 function forum_field_storage_pre_update(EntityInterface $entity, &$skip_fields) {
   $first_call = &drupal_static(__FUNCTION__, array());
 
+  $entity = $entity->getNGEntity();
   if ($entity->entityType() == 'node' && _forum_node_check_node_type($entity)) {
 
     // If the node is published, update the forum index.
@@ -1139,7 +1141,7 @@ function template_preprocess_forum_topic_list(&$variables) {
       $variables['topics'][$id]->new_text = '';
       $variables['topics'][$id]->new_url = '';
       if ($topic->new_replies) {
-        $variables['topics'][$id]->new_text = format_plural($topic->new_replies, '1 new post<span class="visually-hidden"> in topic %title</span>', '@count new posts<span class="visually-hidden"> in topic %title</span>', array('%title' => $variables['topics'][$id]->title));
+        $variables['topics'][$id]->new_text = format_plural($topic->new_replies, '1 new post<span class="visually-hidden"> in topic %title</span>', '@count new posts<span class="visually-hidden"> in topic %title</span>', array('%title' => $variables['topics'][$id]->label()));
         $variables['topics'][$id]->new_url = url('node/' . $topic->id(), array('query' => comment_new_page_count($topic->comment_count, $topic->new_replies, $topic), 'fragment' => 'new'));
       }
 
diff --git a/core/modules/node/lib/Drupal/node/NodeFormController.php b/core/modules/node/lib/Drupal/node/NodeFormController.php
index 93a13d1..2281a6f 100644
--- a/core/modules/node/lib/Drupal/node/NodeFormController.php
+++ b/core/modules/node/lib/Drupal/node/NodeFormController.php
@@ -191,7 +191,7 @@ public function form(array $form, array &$form_state) {
       '#title' => t('Authored by'),
       '#maxlength' => 60,
       '#autocomplete_path' => 'user/autocomplete',
-      '#default_value' => !empty($node->name) ? $node->name : '',
+      '#default_value' => $node->getAuthorId()? $node->getAuthor()->getUsername() : '',
       '#weight' => -1,
       '#description' => t('Leave blank for %anonymous.', array('%anonymous' => $user_config->get('anonymous'))),
     );
@@ -332,11 +332,11 @@ public function validate(array $form, array &$form_state) {
     }
 
     // Validate the "authored by" field.
-    if (!empty($node->name) && !($account = user_load_by_name($node->name))) {
+    if (!empty($form_state['values']['name']) && !($account = user_load_by_name($form_state['values']['name']))) {
       // The use of empty() is mandatory in the context of usernames
       // as the empty string denotes the anonymous user. In case we
       // are dealing with an anonymous user we set the user ID to 0.
-      form_set_error('name', t('The username %name does not exist.', array('%name' => $node->name)));
+      form_set_error('name', t('The username %name does not exist.', array('%name' => $form_state['values']['name'])));
     }
 
     // Validate the "authored on" field.
@@ -440,13 +440,11 @@ public function buildEntity(array $form, array &$form_state) {
     $entity = parent::buildEntity($form, $form_state);
     // A user might assign the node author by entering a user name in the node
     // form, which we then need to translate to a user ID.
-    if (!empty($form_state['values']['name'])) {
-      if ($account = user_load_by_name($form_state['values']['name'])) {
-        $entity->setAuthorId($account->id());
-      }
-      else {
-        $entity->setAuthorId(0);
-      }
+    if (!empty($form_state['values']['name']) && $account = user_load_by_name($form_state['values']['name'])) {
+      $entity->setAuthorId($account->id());
+    }
+    else {
+      $entity->setAuthorId(0);
     }
 
     if (!empty($form_state['values']['date']) && $form_state['values']['date'] instanceOf DrupalDateTime) {
diff --git a/core/modules/node/lib/Drupal/node/Plugin/views/row/Rss.php b/core/modules/node/lib/Drupal/node/Plugin/views/row/Rss.php
index 640f00b..1fe68ef 100644
--- a/core/modules/node/lib/Drupal/node/Plugin/views/row/Rss.php
+++ b/core/modules/node/lib/Drupal/node/Plugin/views/row/Rss.php
@@ -121,7 +121,7 @@ public function render($row) {
       ),
       array(
         'key' => 'dc:creator',
-        'value' => $node->name,
+        'value' => $node->getAuthor()->getUsername(),
       ),
       array(
         'key' => 'guid',
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeTranslationUITest.php b/core/modules/node/lib/Drupal/node/Tests/NodeTranslationUITest.php
index dac3575..6861c52 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeTranslationUITest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeTranslationUITest.php
@@ -69,7 +69,7 @@ protected function getNewEntityValues($langcode) {
    * Overrides \Drupal\content_translation\Tests\ContentTranslationUITest::getFormSubmitAction().
    */
   protected function getFormSubmitAction(EntityInterface $entity) {
-    if ($entity->status) {
+    if ($entity->isPublished()) {
       return t('Save and unpublish');
     }
     return t('Save and keep unpublished');
diff --git a/core/modules/node/node.pages.inc b/core/modules/node/node.pages.inc
index 458c93b..fb166c1 100644
--- a/core/modules/node/node.pages.inc
+++ b/core/modules/node/node.pages.inc
@@ -110,21 +110,6 @@ function node_add($node_type) {
  */
 function node_preview(NodeInterface $node) {
   if (node_access('create', $node) || node_access('update', $node)) {
-    // Load the user's name when needed.
-    if (isset($node->name)) {
-      // The use of isset() is mandatory in the context of user IDs, because
-      // user ID 0 denotes the anonymous user.
-      if ($user = user_load_by_name($node->name)) {
-        $node->setAuthorId($user->id());
-      }
-      else {
-        $node->setAuthorId(0); // anonymous user
-      }
-    }
-    elseif ($node->getAuthorId()) {
-      $user = $node->getAuthor();
-      $node->name = $user->getUsername();
-    }
 
     $node->changed = REQUEST_TIME;
 
diff --git a/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.module b/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.module
index 1baa48e..fb217f2 100644
--- a/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.module
+++ b/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.module
@@ -29,10 +29,11 @@ function node_access_test_language_node_access_records(EntityInterface $node) {
   // Create grants for each translation of the node.
   foreach ($node->getTranslationLanguages() as $langcode => $language) {
     // If the translation is not marked as private, grant access.
+    $translation = $node->getTranslation($langcode);
     $grants[] = array(
       'realm' => 'node_access_language_test',
       'gid' => 7888,
-      'grant_view' => empty($node->field_private[$langcode][0]['value']) ? 1 : 0,
+      'grant_view' => empty($translation->field_private->value) ? 1 : 0,
       'grant_update' => 0,
       'grant_delete' => 0,
       'priority' => 0,
diff --git a/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginTestBase.php
index c580338..c73fd67 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginTestBase.php
@@ -89,7 +89,7 @@ public function setUp() {
         'class' => 'Drupal\plugin_test\Plugin\plugin_test\mock_block\MockComplexContextBlock',
         'context' => array(
           'user' => array('class' => 'Drupal\user\UserInterface'),
-          'node' => array('class' => 'Drupal\Core\Entity\EntityBCDecorator'),
+          'node' => array('class' => 'Drupal\node\NodeInterface'),
         ),
       ),
     );
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FieldUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FieldUpgradePathTest.php
index c2340f4..e22f5e3 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FieldUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FieldUpgradePathTest.php
@@ -6,7 +6,9 @@
  */
 
 namespace Drupal\system\Tests\Upgrade;
-use Drupal\Core\Language\Language;
+
+use Drupal\Core\Entity\DatabaseStorageController;
+use Drupal\field\Plugin\Core\Entity\Field;
 
 /**
  * Tests upgrade of system variables.
@@ -209,16 +211,10 @@ function testFieldUpgradeToConfig() {
     // The deleted field uuid and deleted instance field_uuid must match.
     $this->assertEqual($deleted_field['uuid'], $deleted_instance['field_uuid']);
 
-    // Check that pre-existing deleted field values are read correctly.
-    $entity = _field_create_entity_from_ids((object) array(
-      'entity_type' => 'node',
-      'bundle' => 'article',
-      'entity_id' => 2,
-      'revision_id' => 2,
-    ));
-    field_attach_load('node', array(2 => $entity), FIELD_LOAD_CURRENT, array('instance' => entity_create('field_instance', $deleted_instance)));
-    $deleted_value = $entity->get('test_deleted_field');
-    $this->assertEqual($deleted_value->value, 'Some deleted value');
+    // Check that pre-existing deleted field table is renamed correctly.
+    $field_entity = new Field($deleted_field);
+    $table_name = _field_sql_storage_tablename($deleted_field);
+    $this->assertEqual("field_deleted_data_" . substr(hash('sha256', $deleted_field['uuid']), 0, 10), $table_name);
 
     // Check that creation of a new node works as expected.
     $value = $this->randomName();
diff --git a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/MockBlockManager.php b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/MockBlockManager.php
index a897160..386841b 100644
--- a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/MockBlockManager.php
+++ b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/MockBlockManager.php
@@ -91,7 +91,7 @@ public function __construct() {
       'class' => 'Drupal\plugin_test\Plugin\plugin_test\mock_block\MockComplexContextBlock',
       'context' => array(
         'user' => array('class' => 'Drupal\user\UserInterface'),
-        'node' => array('class' => 'Drupal\Core\Entity\EntityBCDecorator'),
+        'node' => array('class' => 'Drupal\node\NodeInterface'),
       ),
     ));
 
diff --git a/core/modules/translation/lib/Drupal/translation/Tests/TranslationTest.php b/core/modules/translation/lib/Drupal/translation/Tests/TranslationTest.php
index 498bd33..c021e61 100644
--- a/core/modules/translation/lib/Drupal/translation/Tests/TranslationTest.php
+++ b/core/modules/translation/lib/Drupal/translation/Tests/TranslationTest.php
@@ -112,7 +112,7 @@ function testContentTranslation() {
     $edit["body[$langcode][0][value]"] = $this->randomName();
     $this->drupalPost('node/add/page', $edit, t('Save'), array('query' => array('translation' => $node->id(), 'language' => 'es')));
     $duplicate = $this->drupalGetNodeByTitle($edit["title"]);
-    $this->assertEqual($duplicate->tnid, 0, 'The node does not have a tnid.');
+    $this->assertEqual($duplicate->tnid->value, 0, 'The node does not have a tnid.');
 
     // Update original and mark translation as outdated.
     $node_body = $this->randomName();
@@ -171,7 +171,7 @@ function testLanguageSwitchLinks() {
     // Unpublish the Spanish translation to check that the related language
     // switch link is not shown.
     $this->drupalLogin($this->admin_user);
-    $this->drupalPost("node/$translation_es->nid/edit", array(), t('Save and unpublish'));
+    $this->drupalPost('node/' . $translation_es->id() . '/edit', array(), t('Save and unpublish'));
     $this->drupalLogin($this->translator);
     $this->assertLanguageSwitchLinks($node, $translation_es, FALSE);
 
@@ -181,7 +181,7 @@ function testLanguageSwitchLinks() {
     $edit = array('language_interface[enabled][language-url]' => FALSE);
     $this->drupalPost('admin/config/regional/language/detection', $edit, t('Save settings'));
     $this->resetCaches();
-    $this->drupalPost("node/$translation_es->nid/edit", array(), t('Save and publish'));
+    $this->drupalPost('node/' . $translation_es->id() . '/edit', array(), t('Save and publish'));
     $this->drupalLogin($this->translator);
     $this->assertLanguageSwitchLinks($node, $translation_es, TRUE, 'node');
   }
@@ -396,7 +396,7 @@ function createTranslation(EntityInterface $node, $title, $body, $langcode) {
     // Check to make sure that translation was successful.
     $translation = $this->drupalGetNodeByTitle($title);
     $this->assertTrue($translation, 'Node found in database.');
-    $this->assertTrue($translation->tnid == $node->id(), 'Translation set id correctly stored.');
+    $this->assertTrue($translation->tnid->value == $node->id(), 'Translation set id correctly stored.');
 
     return $translation;
   }
@@ -449,10 +449,9 @@ function assertLanguageSwitchLinks(NodeInterface $node, $translation, $find = TR
     }
 
     $result = TRUE;
-    $languages = language_list();
-    $page_language = $languages[$node->language()->id];
-    $translation_language = $languages[$translation->langcode];
-    $url = url("node/$translation->nid", array('language' => $translation_language));
+    $page_language = $node->language();
+    $translation_language = $translation->language();
+    $url = url('node/' . $translation->id(), array('language' => $translation_language));
 
     $this->drupalGet('node/' . $node->id(), array('language' => $page_language));
 
diff --git a/core/modules/translation/translation.module b/core/modules/translation/translation.module
index 7f65448..e237ad2 100644
--- a/core/modules/translation/translation.module
+++ b/core/modules/translation/translation.module
@@ -331,8 +331,8 @@ function translation_node_prepare_form(NodeInterface $node, $form_display, $oper
     }
 
     // Ensure we don't have an existing translation in this language.
-    if (!empty($source_node->tnid)) {
-      $translations = translation_node_get_translations($source_node->tnid);
+    if (!empty($source_node->tnid->value)) {
+      $translations = translation_node_get_translations($source_node->tnid->value);
       if (isset($translations[$langcode])) {
         drupal_set_message(t('A translation of %title in %language already exists, a new %type will be created instead of a translation.', array('%title' => $source_node->label(), '%language' => $language_list[$langcode]->name, '%type' => $node->bundle())), 'error');
         return;
@@ -462,7 +462,7 @@ function translation_remove_from_set(NodeInterface $node) {
       // If the node being removed was the source of the translation set,
       // we pick a new source - preferably one that is up to date.
       if ($node->tnid->value == $node->id()) {
-        $new_tnid = db_query('SELECT nid FROM {node} WHERE tnid = :tnid ORDER BY translate ASC, nid ASC', array(':tnid' => $node->tnid))->fetchField();
+        $new_tnid = db_query('SELECT nid FROM {node} WHERE tnid = :tnid ORDER BY translate ASC, nid ASC', array(':tnid' => $node->tnid->value))->fetchField();
         db_update('node')
           ->fields(array('tnid' => $new_tnid))
           ->condition('tnid', $node->tnid->value)