Add a note about using reload().
diff --git a/Doc/tutorial/modules.rst b/Doc/tutorial/modules.rst
index 6e45f64..975e13e 100644
--- a/Doc/tutorial/modules.rst
+++ b/Doc/tutorial/modules.rst
@@ -103,6 +103,13 @@
This imports all names except those beginning with an underscore (``_``).
+.. note::
+
+ For efficiency reasons, each module is only imported once per interpreter
+ session. Therefore, if you change your modules, you must restart the
+ interpreter -- or, if it's just one module you want to test interactively,
+ use :func:`reload`, e.g. ``reload('modulename')``.
+
.. _tut-modulesasscripts: