It is an interesting book, but you have to take it with a grain of salt. The author is constantly trashing Jobs, primarily for spending too much money too quickly, being a bad businessperson, etc. Over, and over, and over again, long after he's made his point (and he supplies some good evidence he's right). But it is still the only book I know of dedicated primarily to the history of NeXT, and there's lots of great information.
I've read it (misplaced my copy though) and pergamon basically has it right. There is some interesting stuff though.
It is available for a lot cheaper from Amazon, check the link below. My local library actually had a copy a few years ago, which was a shock to me.
http://www.amazon.com/gp/offer-listing/0689121350/ref=sr_1_1_olp?ie=UTF8&qid=1309560118&sr=8-1&condition=used