diff --git a/bk000-preface.xml b/bk000-preface.xml
index 39f74870..5a3348fe 100644
--- a/bk000-preface.xml
+++ b/bk000-preface.xml
@@ -8,7 +8,7 @@
         <title>Preface</title>
         <?dbhtml stop-chunking?>
         <xi:include href="../common/section_dochistory.xml"/>
-    </preface>
+     </preface>
     <appendix xml:id="under-construction">
         <title>OpenStack Training Guides Are Under Construction</title>
         <para>We need your help! This is a community driven project to provide the user group community