diff --git a/beautiful-racket/br/demo/txtadv/expander.rkt b/beautiful-racket/br/demo/txtadv/expander.rkt
index b07c10f..6c714ab 100644
--- a/beautiful-racket/br/demo/txtadv/expander.rkt
+++ b/beautiful-racket/br/demo/txtadv/expander.rkt
@@ -31,6 +31,9 @@
          (do-place)))))
 
 
+;; ==============================================================
+;; Process parse trees from the reader:
+
 (provide txtadv-program)
 (define #'txtadv-program #'module-begin)