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 his first full length on Sire Records (home to Madonna and Depeche Mode), which helped usher in Richard D. James, for whom Aphex Twin is but one of numerous monikers, as a major force in music,...