diff --git a/core/modules/book/src/BookManager.php b/core/modules/book/src/BookManager.php
index e0587c3..e2a1f2f 100644
--- a/core/modules/book/src/BookManager.php
+++ b/core/modules/book/src/BookManager.php
@@ -59,7 +59,7 @@ class BookManager implements BookManagerInterface {
   /**
    * Book Storage.
    *
-   * @var BookStorageInterface
+   * @var: \Drupal\book\BookStorageInteface
    */
   protected $bookStorage;
 
diff --git a/core/modules/book/src/BookStorage.php b/core/modules/book/src/BookStorage.php
index 03f0f36..1b61e17 100644
--- a/core/modules/book/src/BookStorage.php
+++ b/core/modules/book/src/BookStorage.php
@@ -10,7 +10,7 @@
 use Drupal\Core\Database\Connection;
 
 /**
- * Defines a Controller class for books.
+ * Defines a storage class for books.
  */
 class BookStorage implements BookStorageInterface {
 
diff --git a/core/modules/book/src/BookStorageInterface.php b/core/modules/book/src/BookStorageInterface.php
index d02fce9..678021d 100644
--- a/core/modules/book/src/BookStorageInterface.php
+++ b/core/modules/book/src/BookStorageInterface.php
@@ -8,12 +8,12 @@
 namespace Drupal\book;
 
 /**
- * Defines a common interface for book controller classes.
+ * Defines a common interface for book storage classes.
  */
 interface BookStorageInterface {
 
   /**
-   * Get books.
+   * Gets books (the highest positioned book links).
    *
    * @return array
    *   An array of book ids.
@@ -21,7 +21,7 @@
   public function getBooks();
 
   /**
-   * Load books.
+   * Loads books.
    *
    * @param array $nids
    *   An array of nids.
@@ -32,7 +32,7 @@ public function getBooks();
   public function loadMultiple($nids);
 
   /**
-   * Get child relative depth.
+   * Gets child relative depth.
    *
    * @param array $book_link
    *   The book link.
@@ -46,7 +46,7 @@ public function loadMultiple($nids);
   public function getChildRelativeDepth($book_link, $max_depth);
 
   /**
-   * Delete a book entry.
+   * Deletes a book entry.
    *
    * @param int|string $nid
    *   Deletes a book entry.
@@ -57,7 +57,7 @@ public function getChildRelativeDepth($book_link, $max_depth);
   public function delete($nid);
 
   /**
-   * Load book's children using it's parent's id.
+   * Loads book's children using it's parent's id.
    *
    * @param int|string $pid
    *   The parent's book nid.
@@ -68,7 +68,7 @@ public function delete($nid);
   public function loadBookChildren($pid);
 
   /**
-   * Build tree data used for the menu tree.
+   * Builds tree data used for the menu tree.
    *
    * @param int|string $bid
    *   The ID of the book that we are building the tree for.
@@ -85,7 +85,7 @@ public function loadBookChildren($pid);
   public function getBookMenuTree($bid, $parameters, $min_depth, $max_depth);
 
   /**
-   * Insert a book link.
+   * Inserts a book link.
    *
    * @param array $link
    *   The link array to be inserted in the database.
@@ -99,7 +99,7 @@ public function insert($link, $parents);
 
 
   /**
-   * Update a book link entry.
+   * Updates book reference for links that were moved between books.
    *
    * @param int|string $nid
    *   The nid of the book entry to be updated.
diff --git a/core/modules/book/tests/src/BookManagerTest.php b/core/modules/book/tests/src/BookManagerTest.php
index 7fcdaff..f26b41c 100644
--- a/core/modules/book/tests/src/BookManagerTest.php
+++ b/core/modules/book/tests/src/BookManagerTest.php
@@ -58,7 +58,7 @@ class BookManagerTest extends UnitTestCase {
   /**
    * Book Storage.
    *
-   * @var BookStorageInterface
+   * @var: \Drupal\book\BookStorageInteface
    */
   protected $bookStorage;