diff --git a/segpy/encoding.py b/segpy/encoding.py
index c02d2ca..b1a4a07 100644
--- a/segpy/encoding.py
+++ b/segpy/encoding.py
@@ -1,3 +1,10 @@
+"""Support for the text encodings used in SEG Y.
+
+SEG Y data can contain textual data encoded in either ASCII
+or EBCDIC format. This module contains tools for detecting those
+encodings.
+"""
+
 ASCII = 'ascii'
 EBCDIC = 'cp037'
 
@@ -29,6 +36,7 @@ COMMON_CHARS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789:_
 COMMON_EBCDIC_CHARS = set(COMMON_CHARS.encode(EBCDIC))
 COMMON_ASCII_CHARS = set(COMMON_CHARS.encode(ASCII))
 
+
 def guess_encoding(bs, threshold=0.5):
     """Try to determine whether the encoding of byte stream b is an ASCII string or an EBCDIC string.
 
@@ -73,6 +81,4 @@ def guess_encoding(bs, threshold=0.5):
     if ebcdic_freq < threshold and ascii_freq < threshold:
         return None
 
-
-
     return None