diff --git a/content/refactoring-concepts.md b/content/refactoring-concepts.md
index 78039ad..aec5cda 100644
--- a/content/refactoring-concepts.md
+++ b/content/refactoring-concepts.md
@@ -5,4 +5,5 @@
 Topics:
 - Pure functions
 - Design patterns: functional design vs. object-oriented design
+- From classes to functions
 - How to design your code before writing it: document-driven development