From the expanding classical horizons of Mahler, Satie and Debussy to the revolutions in electronic music inaugurated by Stockhausen and Cage; from the Indian-influenced minimalism of Phillip Glass and Terry Riley to the 'unlocking' sound worlds of Brian Eno and Arvo Part; through the epoch-defining music of rock maestros The Beatles a nd Jimi Hendrix to the pure electronic creations of Kraftwerk, Goldie and Trance - this drift through technology, Minimalism, the rock era and Techno is earthed by the development in Ambient Sound, to the author the most important breakthrough in music of the past one hundred years.