diff --git a/core/modules/book/src/Plugin/Block/BookNavigationBlock.php b/core/modules/book/src/Plugin/Block/BookNavigationBlock.php
index b232fbf..6967077 100644
--- a/core/modules/book/src/Plugin/Block/BookNavigationBlock.php
+++ b/core/modules/book/src/Plugin/Block/BookNavigationBlock.php
@@ -156,9 +156,12 @@ public function build() {
       }
     }
     elseif ($current_bid) {
-      // Only display this block when the user is browsing a book.
-      $query = \Drupal::entityQuery('node');
-      $nid = $query->condition('nid', $node->book['bid'], '=')->execute();
+      // Only display this block when the user is browsing a book and do
+      // not show unpublished books.
+      $nid = \Drupal::entityQuery('node')
+        ->condition('nid', $node->book['bid'], '=')
+        ->condition('status', NODE_PUBLISHED)
+        ->execute();
 
       // Only show the block if the user has view access for the top-level node.
       if ($nid) {