diff --git a/modules/book.module b/modules/book.module
index 0a207c7008d674f130a59161182d7d2537e58137..e4c018882a86af61a5c6fc1b584d9085e721101f 100644
--- a/modules/book.module
+++ b/modules/book.module
@@ -585,7 +585,7 @@ function book_tree($parent = 0, $depth = 3, $unfold = array()) {
   }
 
   if ($tree = book_tree_recurse($parent, $depth, $children, $unfold)) {
-    return '<ul>'. $tree .'</ul>';
+    return '<div class="menu"><ul>'. $tree .'</ul></div>'; 
   }
 }
 
diff --git a/modules/book/book.module b/modules/book/book.module
index 0a207c7008d674f130a59161182d7d2537e58137..e4c018882a86af61a5c6fc1b584d9085e721101f 100644
--- a/modules/book/book.module
+++ b/modules/book/book.module
@@ -585,7 +585,7 @@ function book_tree($parent = 0, $depth = 3, $unfold = array()) {
   }
 
   if ($tree = book_tree_recurse($parent, $depth, $children, $unfold)) {
-    return '<ul>'. $tree .'</ul>';
+    return '<div class="menu"><ul>'. $tree .'</ul></div>'; 
   }
 }