These two are my go to's:
Culture Clash: Jean Donaldson: 9781617811128: Amazon.com: Books
The Other End of the Leash: Why We Do What We Do Around Dogs: Patricia B. McConnell: 9780345446787: Amazon.com: Books
My friend is looking at taking a trainer training program. The reading for the first module is as follows:
Mandatory Reading Material:
Excel-erated Learning: Explaining in English How Dogs Learn and How Best to TeachThem, by Pamela j. Reid, Ph. D
The Culture Clash, by Jean Donaldson
Donʼt Shoot the Dog, by Karen Pryor
Recommended Reading Material:Calming Signals, by Turid Ruugas
Note: I haven't read those books other than culture clash. i actually just picked up don't shoot the dog from teh library today.