Extravagantly opaque, willfully vaporous - Aphex Twin's Selected Ambient Works Volume II, released by the estimable British label Warp Records in 1994, rejuvenated ambient music for the Internet Age that was just dawning. In the United States, it was Richard D. James's first full length on Sire Records (home to Madonna and Depeche Mode) under the moniker Aphex Twin; Sire helped usher him in as a major force in music, electronic or otherwise. Faithful to Brian Eno's definition of ambient music, Selected Ambient Works Volume II was intentionally functional: it furnished chill out rooms, the sanctuaries amid intense raves. Choreographers and film directors began to employ it to their own ends, and in the intervening decades this background music came to the fore, adapted by classical composers who reverse-engineered its fragile textures for performance on acoustic instruments. Simultaneously, ''ambient'' has moved from esoteric sound art to central tenet of online culture. This book contends that despite a reputation for being beatless, the album exudes percussive curiosity, providing a sonic metaphor for our technologically mediated era of countless synchronized nanosecond metronomes.