diff --git a/book.asciidoc b/book.asciidoc
index c3bf72f1..6312cb72 100644
--- a/book.asciidoc
+++ b/book.asciidoc
@@ -2,4 +2,4 @@
 
 = Mastering Bitcoin
 
-include::appdx-sx.asciidoc[]
\ No newline at end of file
+include::appdx-pycoin.asciidoc[]
\ No newline at end of file