2 Books:
Combatting Cult Mind Control by Steven Hassan. He demonstrates how to decipher dangerous mind control techniques. He never names Jehovah's Witnesses in his book, so he doesn't "have it out for them", so to speak. He was in a mind control group himself and knows the psychology behind what makes such groups effective, and how to spot them.
Crisis of Conscience by Ray Franz. He was on the Governing Body of Jehovah's Witnesses, the highest position in the org. He had insight into what took place behind closed doors. Interestingly, he was never sued for libel.
jwfacts.com works for many, as already mentioned.