Extremely boring. Only had to read it because of class.
Look, I think there's a bunch of good information in here, but it suffers from the typical textbook problem of each chapter basically being a lit review of everything that exists on the topic, disguised behind a thin veneer of a narrative. It's not readable.
Obviously, if you're doing your Ph.D. in negotiation and what you're after is the most comprehensive, authoritative reference about negotiation theory, then this is your go-to resource. However, for the rest of us in the real world (i.e. not in academia inventing laboratory experiments that even the authors admit are not representative of actual negotiations), you can skip it.