I imagine for some, my comments will be taken as some sort of school rivalry, and for those who choose to take this view, so be it. I challenge you to find anything really substantive though that hasn't already been written about.
That said, the book was a complete let down. The authors, from the prestigious Kellogs Graduate School of Management at Northwestern University, are clearly leveraging their affiliation with the school. Unfortunately, the book falls well short of what one would expect from two "Distiguished Professors of Dispute Resolution and Organizations."
While the authors bring in many real life examples of various studies, the book is too simplistic and fails to dig beyond the obvious. One such study explained that experienced negotiators who had completed a training course, did better in a controlled negotiation than experienced negotiators who had not undergone the same training. Experience alone will not make you a good negotiator. Then of course, there is the insightful "Smiling made her seem more friendly so she got more tips." (paraphrased)
I was also dissappointed in the authors' consistent reference to the other negotiator as the "opponent." How does one expect to expand the pie and be thought of as "friendly" when you are always thinking of the other side as an opponent?
Check it out at the library if you must, but save your money.