diff --git a/src/pkg/exp/README b/src/pkg/exp/README
new file mode 100644
index 0000000000..e602e3ac9f
--- /dev/null
+++ b/src/pkg/exp/README
@@ -0,0 +1,3 @@
+This directory tree contains experimental packages and
+unfinished code that is subject to even more change than the
+rest of the Go tree.