diff --git a/core/modules/book/book.admin.inc b/core/modules/book/book.admin.inc
index ff5dac8..7ef0ae1 100644
--- a/core/modules/book/book.admin.inc
+++ b/core/modules/book/book.admin.inc
@@ -55,7 +55,7 @@ function book_admin_overview() {
  */
 function book_admin_edit($form, $form_state, EntityInterface $node) {
   drupal_set_title($node->label());
-  $form['#node'] = $node;
+  $form_state['entity'] = $node;
   _book_admin_table($node, $form);
   $form['save'] = array(
     '#type' => 'submit',
@@ -126,11 +126,11 @@ function book_admin_edit_submit($form, &$form_state) {
   if ($updated) {
     // Flush static and cache.
     drupal_static_reset('book_menu_subtree_data');
-    $cid = 'links:' . $form['#node']->book['menu_name'] . ':subtree-cid:' . $form['#node']->book['mlid'];
+    $cid = 'links:' . $form_state['entity']->book['menu_name'] . ':subtree-cid:' . $form_state['entity']->book['mlid'];
     cache('menu')->delete($cid);
   }
 
-  drupal_set_message(t('Updated book %title.', array('%title' => $form['#node']->label())));
+  drupal_set_message(t('Updated book %title.', array('%title' => $form_state['entity']->label())));
 }
 
 /**
diff --git a/core/modules/book/book.pages.inc b/core/modules/book/book.pages.inc
index 2418591..3887789 100644
--- a/core/modules/book/book.pages.inc
+++ b/core/modules/book/book.pages.inc
@@ -141,7 +141,7 @@ function book_outline_form($form, &$form_state, EntityInterface $node) {
   if (!isset($node->book['parent_depth_limit'])) {
     $node->book['parent_depth_limit'] = _book_parent_depth_limit($node->book);
   }
-  $form['#node'] = $node;
+  $form_state['entity'] = $node;
   $form['#id'] = 'book-outline';
   _book_add_form_elements($form, $form_state, $node);
 
@@ -170,7 +170,7 @@ function book_outline_form($form, &$form_state, EntityInterface $node) {
  * @see book_outline_form_submit()
  */
 function book_remove_button_submit($form, &$form_state) {
-  $form_state['redirect'] = 'node/' . $form['#node']->nid . '/outline/remove';
+  $form_state['redirect'] = 'node/' . $form_state['entity']->nid . '/outline/remove';
 }
 
 /**
@@ -179,7 +179,7 @@ function book_remove_button_submit($form, &$form_state) {
  * @see book_remove_button_submit()
  */
 function book_outline_form_submit($form, &$form_state) {
-  $node = $form['#node'];
+  $node = $form_state['entity'];
   $form_state['redirect'] = "node/" . $node->nid;
   $book_link = $form_state['values']['book'];
   if (!$book_link['bid']) {
@@ -216,7 +216,7 @@ function book_outline_form_submit($form, &$form_state) {
  * @ingroup forms
  */
 function book_remove_form($form, &$form_state, EntityInterface $node) {
-  $form['#node'] = $node;
+  $form_state['entity'] = $node;
   $title = array('%title' => $node->label());
 
   if ($node->book['has_children']) {
@@ -233,7 +233,7 @@ function book_remove_form($form, &$form_state, EntityInterface $node) {
  * Form submission handler for book_remove_form().
  */
 function book_remove_form_submit($form, &$form_state) {
-  $node = $form['#node'];
+  $node = $form_state['entity'];
   if (_book_node_is_removable($node)) {
     menu_link_delete($node->book['mlid']);
     db_delete('book')