Although the title of this 2000 book would make it seem as if it is mostly about "ambient" music in the sense of electronica, that is actually only a fairly small part of the book. It covers the classical music background (e.g., Mahler, Satie, Debussy) as well as the innovative "post-classical" composers (e.g., Cage, Stockhausen, Feldman) that influenced later popular styles. Then he surveys mimimalism in the form of LaMonte Young, Terry Riley, Steve Reich, Philip Glass, etc., as well as true "ambient" pioneers such as Brian Eno and Harold Budd---even briefly covering Windham Hill and "New Age" music.
Then he surveys the Rock era--from Leo Fender and Les Paul to the Beatles, Stones, Dylan, and so on. Then he moves to "Psychedelia" (the Byrds, the Doors, etc.), and to progressive rock (such as Pink Floyd, Keith Emerson, Yes), and various other artists (such as Jean-Michael Jarre, Vangelis, Robert Fripp, John McLaughlin, etc.).
In fact, the only complaint I have about the book is that it doesn't include many ambient artists prominent in the American scene (notably Steve Roach, Vidna Obmana, Robert Rich, Robert Scott Thompson, John Foxx, etc.).
Here are some quotations from the book:
"(The Theremin) was the first of the pioneering electronic devices to hit the top of the charts... firstly on The Beach Boys' 'Good Vibrations' single of 1966 and secondly on Led Zeppelin's second album, where its siren-like sound filled in the stuttering guitar masonry of ... 'Whole Lotta Love.'" (Pg. 24) "When ... Switched on Bach was a million seller in 1968, (Walter) Carlos became one of the most famous electronic musicians in history. The album thrust the idea of the synthesizer as a musical instrument firmly into the public consciousness and kick-started the use of keyboard synthesizers in all types of popular music. Carlos also became the most famous transsexual composer ... Following its success, Walter became Wendy after an operation in 1972, a period which saw her begin to explore various parameters of Ambient music." (Pg. 70) "According to Jon Hassell, 'The history of drugs in America is inextricably interlaced with early Minimalism. There was a need for a music that one could actually enjoy listening to and that you could float away to.' Finally there was the very social nature of the music. No movement has had so much interaction and cross-pollination from all the main parties." (Pg. 92-93) "When Techno and Drum and Bass were absorbed by British Asian musicians a whole new revolution occurred. People like Asian Dub Foundation and most visibly Talvin Singh created genuine fusions of Indian classical music and breakbeat electronics... Of equal importance was (Singh's) London club Anokha (meaning 'unique'), which attracted young Asians and a multicultural audience to hear barrier-breaking blends of East and West." (Pg. 454)