Index: TECH/ListUtils.cls.xml
===================================================================
diff -u -r1627 -r1655
--- TECH/ListUtils.cls.xml	(.../ListUtils.cls.xml)	(revision 1627)
+++ TECH/ListUtils.cls.xml	(.../ListUtils.cls.xml)	(revision 1655)
@@ -708,6 +708,21 @@
   	quit List
 ]]></Implementation>
 </Method>
+
+<Method name="Complement">
+<ClassMethod>1</ClassMethod>
+<FormalSpec>List1:%ListOfDataTypes,List2:%ListOfDataTypes</FormalSpec>
+<ReturnType>%ListOfDataTypes</ReturnType>
+<Implementation><![CDATA[
+	set Complement = ##class(%ListOfDataTypes).%New()
+	set ListIterator = ##class(TECH.ListIterator).%New(List1)
+	while ListIterator.HasNext() {
+		#dim ListItem As TECH.String = ListIterator.Next()
+		if 'List2.Find(ListItem) do Complement.Insert(ListItem)
+	}	
+	quit Complement
+]]></Implementation>
+</Method>
 </Class>