Excellent book, very well written and very readable. This is not just about negotiating but about learning to communicate better - in asking questions and listening better.
It’s a solid book for those interested in negotiations, there are practical elements. I would rank it as ‘intermediate’ - not for beginners, not advanced either. I had the slight impression that the last third of the book was written in a hurry as it’s much less well thought through as the first couple of chapters.