The third _<I>Learning Python_</I>.  

This one was exclusively about the core language.  The former editions' 
coauthor dropped out altogether, and his 1st Edition material was 
trimmed to make room for new content derived from recent live classes.
The result was a cross-app book that reflected the real needs of 
real learners; that probably accounts for most of this title's 
success from this point.

This edition itself had some die-hard fans, and still does, though 
it was a bit light on details, Python 3 was about to convolute the
story badly, and the code pointers added by the publisher were 
arguably annoying (and were cut in 4E).