diff --git a/docs/cmu-user/cmu-user.tex b/docs/cmu-user/cmu-user.tex
index c45631043fe38a99f45e50ca193b29f9ff3fe513..1a6049c894a03a7cd2215a82f9c39cf0e8f2e1e0 100644
--- a/docs/cmu-user/cmu-user.tex
+++ b/docs/cmu-user/cmu-user.tex
@@ -71,6 +71,10 @@ language implementation, programming environment}
 /Title (CMUCL User's Manual)
 /Keywords (\keywords)
 }
+% Add section numbers to the bookmarks, and open 2 levels by default.
+\hypersetup{bookmarksnumbered=true,
+            bookmarksopen=true,
+            bookmarksopenlevel=2}
 \fi
 
 \maketitle