diff --git a/textarea/memoization/memoization.go b/textarea/memoization/memoization.go
index ccb80a9..46c347a 100644
--- a/textarea/memoization/memoization.go
+++ b/textarea/memoization/memoization.go
@@ -1,3 +1,5 @@
+// Package memoization implement a simple memoization cache. It's designed to
+// improve performance in textarea.
 package memoization
 
 import (