diff --git a/preface.asciidoc b/preface.asciidoc
index 93b15dd6..eefaeded 100644
--- a/preface.asciidoc
+++ b/preface.asciidoc
@@ -190,13 +190,13 @@ wallet::
 <?hard-pagebreak?>
 ++++
 
-== Acknowledgments
+=== Acknowledgments
 
-=== Early Release Draft (Github Contributions)
+==== Early Release Draft (Github Contributions)
 
 Many contributors offered comments, corrections and additions to the early-release draft on Github. Thank you all for your contributions to this book. Notable contributors included the following:
 
-==== (Name - Github ID)
+===== (Name - Github ID)
 
 * *Minh T. Nguyen - enderminh: Github contribution editor*
 * Eric Winchell - winchell