diff --git a/Script/eosstorage.py b/Script/eosstorage.py
index 58eae7403daa0f00f09cf3d5c3e95ab019b1c90c..125e48982f4628605a9dd26cee2203a02c2e6575 100644
--- a/Script/eosstorage.py
+++ b/Script/eosstorage.py
@@ -1,5 +1,17 @@
 
-__version__='$Revision$'
+"""
+Provides EOS backend functionalities.
+
+The 'init' function requires one parameter
+
+'keytab':</path/to/keytabfile>
+
+See the 'init' documentation for more details about the keytab naming convention and generation.
+The kerberos authentication is automatically renewed using the keytab file. The token expiration is fetched using kinit.
+
+"""
+
+__version__='$Revision:$'
 
 from subprocess import *
 import castorstorage
@@ -7,8 +19,21 @@ import sys
 import os.path
 import datetime
 
-
 def init(conf):
+    """
+    Initialize the EOS backend module. Requires one parameter:
+    'keytab':</path/to/keytabfile>
+
+    The keytab file must follow this naming convention:
+    /path/to/<username>.keytab
+
+    A keytab file can be generated with:
+    $> /usr/kerberos/sbin/ktutil
+    ktutil: add_entry -password -p <username>@CERN.CH -k 1 -e arcfour-hmac-md5
+    ktutil: add_entry -password -p <username>@CERN.CH -k 1 -e aes256-cts
+    ktutil: wkt <username>.keytab
+    
+    """
     keytabfile = conf['keytab']
     eos = eosstorage(keytabfile)
     globals()['_eos'] = eos