diff --git a/scrapy/trunk/scrapy/xpath/selector.py b/scrapy/trunk/scrapy/xpath/selector.py
index 433970939..8c49c8f97 100644
--- a/scrapy/trunk/scrapy/xpath/selector.py
+++ b/scrapy/trunk/scrapy/xpath/selector.py
@@ -1,3 +1,9 @@
+"""
+XPath selectors 
+
+See documentation in docs/ref/selectors.rst
+"""
+
 import libxml2
 
 from scrapy.http import TextResponse