diff --git a/book b/book
index 448454f..b8099b8 160000
--- a/book
+++ b/book
@@ -1 +1 @@
-Subproject commit 448454f66c4b6d8b62d7cd246d117a903d33834f
+Subproject commit b8099b8b5021d212cd0c0a4c47fb6efac847c6b7