diff --git a/X10D/src/BooleanExtensions/BooleanExtensions.cs b/X10D/src/BooleanExtensions/BooleanExtensions.cs
index 710dcf3..6d83302 100644
--- a/X10D/src/BooleanExtensions/BooleanExtensions.cs
+++ b/X10D/src/BooleanExtensions/BooleanExtensions.cs
@@ -93,7 +93,7 @@ namespace X10D.BooleanExtensions
         /// //       True converts to 1.
         /// </code>
         /// </example>
-        public static long ToDouble(this bool value)
+        public static double ToDouble(this bool value)
         {
             return value.ToByte();
         }