Index: modules/book.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/book.module,v
retrieving revision 1.285
diff -u -F^f -r1.285 book.module
--- modules/book.module	12 Feb 2005 07:51:14 -0000	1.285
+++ modules/book.module	20 Mar 2005 07:51:52 -0000
@@ -439,7 +439,7 @@ function book_nodeapi(&$node, $op, $teas
           foreach ($book as $key => $value) {
             $node->$key = $value;
           }
-          $node = book_navigation($node);
+          $node = theme('book_navigation', $node);
           if ($page) {
             menu_set_location($node->breadcrumb);
           }
@@ -452,8 +452,10 @@ function book_nodeapi(&$node, $op, $teas
 /**
  * Prepares both the custom breadcrumb trail and the forward/backward
  * navigation for a node presented as a book page.
+ *
+ * @ingroup themeable
  */
-function book_navigation($node) {
+function theme_book_navigation($node) {
   $path = book_location($node);
 
   // Construct the breadcrumb: