Just about the best negotiation book I have read. Far more useful than Fisher and Ury ('Getting to Yes')
It's not a list of tips and tricks, but a practical overview of negotiation and how one can go about it successfully. Although the writers are theorists, they are also battle-scarred negotiators, and the book has the feel of day-to-day practicality and intellectual completeness.
They wrote the book for managers but what's written is easily reused for other situations, similar or not.