diff --git a/book b/book
index a614625..4c4ccdb 160000
--- a/book
+++ b/book
@@ -1 +1 @@
-Subproject commit a6146254182f90843fe68e2fb4275ed3b27d62cf
+Subproject commit 4c4ccdb9b2878ed169b4aded8aafe6a1ae234c8d