diff --git a/.gitignore b/.gitignore
index 6985cf1..2b58efa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,6 @@ Cargo.lock
 
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
+
+# Ignore book output
+book