diff --git a/book/src/intro/CHANGELOG.md b/book/src/intro/CHANGELOG.md
index 200f2bf..9824249 100644
--- a/book/src/intro/CHANGELOG.md
+++ b/book/src/intro/CHANGELOG.md
@@ -17,3 +17,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Color words section
 - Dictionary appendix
 - Sentence Structure Semantics chapter
+- Lexicon chapter