diff --git a/book b/book
index c93d734..2b30cef 160000
--- a/book
+++ b/book
@@ -1 +1 @@
-Subproject commit c93d734a3536c21185b3bd6250dc5431017bf71d
+Subproject commit 2b30cef09c03e936a09b2f81f151e785fe264928