What are some good books that can teach practical negotiation skills?

The best book is to refer and inspire the successful negotiators within or outside your firm. There is nothing better than experienced professional people. Watch them and get inspired from them.

To This question I might say, there are numerous books out there that one can learn from, but each individual have different personality and skills, so cannot recommend on in particular, these day I myself use internet index and go through various articles, sometime in Business magazines, all depends on the environment and nature of business. But I can say that we must chose a book that is not out dated and can enhance our knowledge compatible with current time, modern technology, yet in simple language understandable for most people.