Kevin from NERD has a pretty good book. There was a thread about this within the past month, so if you search for it you might be able to find it. I remember there was a couple other ones that people listed but dont remember the names...
Herpetology, Third Edition: An Introductory Biology of Amphibians and Reptiles [Hardcover]
Laurie J. Vitt (Author), Janalee P. Caldwell (Author)
That's a general reading about herps with BIG words but very interesting and Usefull to understand Your scally friends in general.
The Complete Ball Python by Kevin McCurley - that's Ball Pythons Keeper Bible... He is working on second edition now.. but I have no way to know when that's gonn be released...
Pythons of the world vol 2: Ball Pythons : Their History, Natural History, Care and Breeding by David G. ; Barker, Tracy M. Barker
Designer-Morphs, Volume One: Ball Python and Boa Constrictor, A Guide to Mutations and Variations by John Berry
1.0 Striped African House Snake "Marduk"
0.1 Striped African House Snake Ishtar
1.0 black phase Brown House Snake Seth
0.1 black phase Brown House Snake Nephthys
I had considered buying books, but they are expensive and generally out of date by the time they are printed. The breeders websites and forums like this seem the way to go for up to date info.
I would take the money you were going to spend on a book and buy a forum membership.