For cat behaviour, I recommend any of the books by certified animal behaviourist Pam Johnson-Bennett: http://catbehaviorassociates.com/
"Think Like A Cat" and "Twisted Whiskers" would be a good place to start. For overall cat care, The Cat Bible
by Tracie Hotchner is pretty good, and I'm also a big fan of Your Cat: Simple New Secrets to a Longer, Stronger Life
, by Dr. Elizabeth Hodgkins.