diff --git a/singleton/src/main/java/com/iluwatar/singleton/EnumIvoryTower.java b/singleton/src/main/java/com/iluwatar/singleton/EnumIvoryTower.java
index 00ddb79ac..e4c0b26d8 100644
--- a/singleton/src/main/java/com/iluwatar/singleton/EnumIvoryTower.java
+++ b/singleton/src/main/java/com/iluwatar/singleton/EnumIvoryTower.java
@@ -24,6 +24,9 @@ package com.iluwatar.singleton;
 
 /**
  * Enum based singleton implementation. Effective Java 2nd Edition (Joshua Bloch) p. 18
+ *
+ * This implementation is thread safe, however adding any other method and its thread safety
+ * is developers responsibility.
  */
 public enum EnumIvoryTower {