diff --git a/README.md b/README.md
index 285a7d5..8159727 100644
--- a/README.md
+++ b/README.md
@@ -13,3 +13,4 @@ Just run `make` here to build everything, including the book `frap.pdf` and the
 * Chapter 6: `OperationalSemantics.v`
 * Chapter 7: `AbstractInterpretation.v`
 * Chapter 8: `LambdaCalculusAndTypeSoundness.v`
+* Chapter 9: `TypesAndMutation.v`