diff --git a/compound/book/view_macros.pt b/compound/book/view_macros.pt
index 43be71b..c5b1562 100644
--- a/compound/book/view_macros.pt
+++ b/compound/book/view_macros.pt
@@ -30,12 +30,13 @@
          tal:attributes="href pred/targetUrl;
                          title pred/title">
         <img src="/@@/cybertools.icons/arrow_left.png" /></a>
-      <a tal:attributes="href parent/targetUrl;
-                          title parent/title">
+      <a tal:condition="nocall:parent"
+         tal:attributes="href parent/targetUrl;
+                         title parent/title">
         <img src="/@@/cybertools.icons/arrow_up.png" /></a>
-      <a  tal:condition="nocall:succ"
-          tal:attributes="href succ/targetUrl;
-                          title succ/title">
+      <a tal:condition="nocall:succ"
+         tal:attributes="href succ/targetUrl;
+                         title succ/title">
         <img src="/@@/cybertools.icons/arrow_right.png" /></a>
     </div>
   </metal:navigation>