diff --git a/toarstats/__init__.py b/toarstats/__init__.py
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..d33f5b4d191cc97f59b5bf6c2b10c05a06a14469 100644
--- a/toarstats/__init__.py
+++ b/toarstats/__init__.py
@@ -0,0 +1,6 @@
+"""The toarstats package.
+
+This package contains the following two subpackages:
+metrics - calculate metrics on time series
+trends - calculate trends on time series
+"""