I found this pretty frustrating. I don't mind books which are wide-ranging and unafraid to explore the fringes of their subject matter, but this was pretty much *all* fringe, with less than half of it conforming to my expectations of what a book about ambient music should be like. Maybe that's my fault (or the fault of the back cover blurb writer), but I can't really see the relevance of the extended chapter describing in tedious detail the author's journey into the amazon rainforest. So he made a few recordings of insect sounds and local tribes chanting...and?
Similarly, he wanders off topic too often in order to discuss things which he himself finds interesting but which have only the most tenuous of relationships to the ostensible subject matter.
There are some good quotes from Brian Eno and Richard James, and interesting tidbits here and there about acoustics and musicological theory, but it's all too diffuse, woolly and rambling. It's also painfully 90s, with instantly dated references to "cyber-culture" and "virtuality".
Mainly it suffers from being a book about music. Ideally it would be accompanied by a compliation cd so that you could actually hear some of what he's writing about.