diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 076d324b60..1e2b866190 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -374,6 +374,18 @@ To change part of a list you can specify the first and last item to be
 modified.  The value must at least have the number of items in the range: >
 	:let list[3:5] = [3, 4, 5]
 
+To add items to a List in-place, you can use the |+=| operator: >
+	:let listA = [1, 2]
+	:let listA += [3, 4]
+<
+When two variables refer to the same List, changing one List in-place will
+cause the referenced List to be changed in-place: >
+	:let listA = [1, 2]
+	:let listB = listA
+	:let listB += [3, 4]
+	:echo listA
+	[1, 2, 3, 4]
+<
 Adding and removing items from a list is done with functions.  Here are a few
 examples: >
 	:call insert(list, 'a')		" prepend item 'a'