I have both VPI and Nerds books. Nothing against kevin's book but the VPI's book has alot more info and is the better of the 2 in my opinion(is more expensive though) but certainly worth every penny...
I have read both of them as well, and I also highly recommend the VPI book. Though the Complete Ball Python is also an excellent book.
I own the Ball Pythons book by Collete Sutherland and its very good as a "pet store" book goes.
Ball Pythons:
1.3 normal
1.0 pastel
0.1 spider
0.1 het pied
---------------
1.1 Kenyan Sand Boas
---------------
Corns:
1.0 snow
0.1 hypo motley
0.1 sunglow reverse motley
---------------
0.0.1 Green Tree Python