What are the best NLP books for business?

Back when I first started learning NLP in 1991 there were less than 100 books about NLP in print. Now, if you put 'NLP' into the Amazon search facility there are over 6000 results. I'm sure there are good books that I've missed along the way.

So I've decided to do a survey. What are the best books about NLP for applications in business?

Click here to take survey