A few years before his ascendance to iconhood, Brian Eno was a British, ex-Roxy Music rascal who -- like the Velvet Underground in the 1960s -- sought to bridge rock and the avant-garde as a singer, producer, and self-declared "nonmusician." In 1978, he hooked up with Cluster (formerly Kluster), the seminal German duo of Hans Roedelius and Dieter Moebius, pioneers of electronic experimental rock since the early '70s. Their second collaboration, the surreal After the Heat, intimates Eno's interest in dispensing with song forms in favor of contemplative soundscapes known today as "ambient" music. Yet there're a few jagged, warped vocal pieces, like the nightmarish "Broken Head." The two volumes of Begenungen present a mélange of solo, duo, and trio works by all three, with the participation of legendary engineer Conny Plank (1945-1987). These are unbelievably prescient: The motoric reveries "Speed Display" and "Pitch Control" anticipated techno by a few decades, and "Johanneslust" is beguiling pastoral folktronica, realized long before Beth Orton and Kinnie Star were stirrings in their parents' loins.