diff -uw ftplib.rst ftplib-patch.rst
--- ftplib.rst	2010-10-12 14:41:18.425811000 -0400
+++ ftplib-patch.rst	2010-10-12 14:41:59.817808000 -0400
@@ -91,18 +91,18 @@
 
 .. exception:: error_temp
 
-   Exception raised when an error code in the range 400--499 is received.
+   Exception raised when an error code signifying a temporary error is received.
 
 
 .. exception:: error_perm
 
-   Exception raised when an error code in the range 500--599 is received.
+   Exception raised when an error code signifying a permanent error is received.
 
 
 .. exception:: error_proto
 
    Exception raised when a reply is received from the server that does not
-   begin with a digit in the range 1--5.
+   fit the reply code specifications of the File Transfer Protocol.
 
 
 .. data:: all_errors
@@ -199,8 +199,8 @@
 .. method:: FTP.voidcmd(command)
 
    Send a simple command string to the server and handle the response. Return
-   nothing if a response code in the range 200--299 is received. Raise an exception
-   otherwise.
+   nothing if a response code signifying successful completion is received. 
+   Raise an exception otherwise.
 
 
 .. method:: FTP.retrbinary(command, callback[, maxblocksize[, rest]])
@@ -220,9 +220,12 @@
    Retrieve a file or directory listing in ASCII transfer mode.  *command*
    should be an appropriate ``RETR`` command (see :meth:`retrbinary`) or a
    command such as ``LIST``, ``NLST`` or ``MLSD`` (usually just the string
-   ``'LIST'``).  The *callback* function is called for each line with a
-   string argument containing the line with the trailing CRLF stripped.
-   The default *callback* prints the line to ``sys.stdout``.
+   ``'LIST'``).  ``LIST`` retrieves a list of files and information about those
+   files. ``NLST`` retrieves a list of file names. On some servers, ``MLSD``
+   retrieves a machine readable list of files and information about those files.
+   The *callback* function is called for each line with a string argument 
+   containing the line with the trailing CRLF stripped. The default *callback*
+   prints the line to ``sys.stdout``.
 
 
 .. method:: FTP.set_pasv(boolean)
@@ -293,7 +296,7 @@
 
 .. method:: FTP.nlst(argument[, ...])
 
-   Return a list of files as returned by the ``NLST`` command.  The optional
+   Return a list of file names as returned by the ``NLST`` command.  The optional
    *argument* is a directory to list (default is the current server directory).
    Multiple arguments can be used to pass non-standard options to the ``NLST``
    command.