These seem to be the two subjects that interest me most now in days. I thought about making two separate threads (one for cat books and the other for sociology books), but I figured one should be enough.
Any suggestions?
How about both? See Cat Culture: The Social World of a Cat Shelter. Janet Alger, the coauthor, is a sociology professor, BTW.
Cats:
Why Cats Paint: A Theory of Feline Aesthetics, by Heather Busch & Burton Silver – http://www.amazon.com/gp/product/0898156122/qid=1134682175/sr=8-1/ref=pd_bbs_1/104-6165472-8303106?n=507846&s=books&v=glance
Sociology:
The 120 Days of Sodom, by the Marquis de Sade – http://www.amazon.com/gp/product/0802130127/qid=1134682298/sr=1-2/ref=sr_1_2/104-6165472-8303106?s=books&v=glance&n=283155
Social Mindscapes, by Eviatar Zerubavel. A short book (about 100 pages) that presents a very coherent and powerful idea about the social mind.
Mistaken Identity: The Mind-Brain Problem Reconsidered, by Leslie Brothers. Also fairly short, this book is essentially a tirade against neuroism.
If you’re really feeling adventurous, A Mind So Rare: The Evolution of Human Consciousness by Merlin Donald is quite long, but it’s a very thorough explanation of why humanity is what it is today.
The Character of Cats is probably the best book on cat behavior. I also liked Know your cat, which has lots of good kitty pics.
I liked Catwatching by Desmond Morris.
Dsmond Morris says things about cats that simply aren’t true. For one thing he claims male cats will not kill kittens. They will. Also he claims that cats don’t eat grass, they just chew on it. This will come as a surprise to my Zoe, whose poo sometimes contains undigested grass.
You have ruined my world.
It’s fiction, but still a good book series. Catfantastic edited by Andre Norton and Martin H. Greenburg. I own the first of the series , all of the stories in it are quite good. I’m fond of the “Noble Warrior” series written by Andre Norton, (which I’ve read in some of the other books in the series which I own) and want to acquire the rest of the books in the series to see what other adventures he has. The first book also has a story by Mercedes Lackey in it as well.
Damn. Sorry about that. 
My favorite book about cats is The Autobiography of Foudini M. Cat by Susan Fromberg Schaefer.
For a real treat, try to find the audiobook version–it’s read by David Hyde Pierce, and he does a fantastic job. I guarantee that if you like cats, the scene where he describes a cat trying to communicate with a human will cause you to hurt yourself laughing.