One of the indisputable classics of electronica, and a defining document for ambient music in particular, Selected Ambient Works 85-92 is Richard D. James' earliest and most fully realized achievement. Reputedly created on homemade equipment deconstructed from standard synthesizers, the music within takes its cue from club beats and the techno rhythms of rave and acid-house culture. Upon these foundations, however, Aphex Twin weaves melodic tapestries of great subtlety, beauty, and atmospheric texture. "Tha," for example, contains a muted bass-drum pulse that becomes the center for evolving patterns of sound -- a kind of aural mandala. The more driving rhythm of "Heliosphan" also gives rise to the ethereal play of melody. Several tracks, such as "Schottkey 7th Path" and "Hedphelym," have a tense, telescoping ambience that evokes paranoia and a sense of gravity-free floating at once. Other selections show Aphex Twin working more firmly in the techno-dance idiom, but even these display a complexity, elegance, and delicacy rarely heard in the genre. This landmark recording is one of the essential building blocks of any electronica collection.