diff --git a/BUILD.gn b/BUILD.gn
index 1af5ea4..10cefaa 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1,3 +1,25 @@
+#
+#  Copyright (C) 2015 Google, Inc.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at:
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+# This is the root build file for GN. GN will start processing by loading this
+# file, and recursively load all dependencies until all dependencies are either
+# resolved or known not to exist (which will cause the build to fail). So if
+# you add a new build file, there must be some path of dependencies from this
+# file to your new one or GN won't know about it.
+
 # This pulls in main/BUILD.gn and all of its dependencies.
 group("bluetooth") {
   deps = [