diff --git a/core/modules/book/src/BookManager.php b/core/modules/book/src/BookManager.php
index 36614bc..de4a158 100644
--- a/core/modules/book/src/BookManager.php
+++ b/core/modules/book/src/BookManager.php
@@ -9,7 +9,6 @@
 
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Cache\Cache;
-use Drupal\Core\Database\Connection;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Session\AccountInterface;
diff --git a/core/modules/book/src/BookStorageInterface.php b/core/modules/book/src/BookStorageInterface.php
index ea03893..a92dff2 100644
--- a/core/modules/book/src/BookStorageInterface.php
+++ b/core/modules/book/src/BookStorageInterface.php
@@ -16,7 +16,7 @@
    * Gets books (the highest positioned book links).
    *
    * @return array
-   *   An array of book ids.
+   *   An array of book IDs.
    */
   public function getBooks();
 
@@ -24,7 +24,7 @@ public function getBooks();
    * Loads books.
    *
    * @param array $nids
-   *   An array of nids.
+   *   An array of node IDs.
    *
    * @return array
    *   Array of loaded book items.
@@ -52,15 +52,15 @@ public function getChildRelativeDepth($book_link, $max_depth);
    *   Deletes a book entry.
    *
    * @return mixed
-   *   Number of deleted book entires.
+   *   Number of deleted book entries.
    */
   public function delete($nid);
 
   /**
-   * Loads book's children using it's parent's id.
+   * Loads book's children using it's parent ID.
    *
    * @param int $pid
-   *   The parent's book nid.
+   *   The book's parent ID.
    *
    * @return array
    *   Array of loaded book items.
@@ -113,7 +113,7 @@ public function insert($link, $parents);
   public function update($nid, $fields);
 
   /**
-   * Update the book id of the book link that it's beeing moved.
+   * Update the book ID of the book link that it's being moved.
    *
    * @param int $bid
    *   The ID of the book whose children we move.