Always at least three steps ahead of contemporary popular music, Can were the leading avant-garde rock group of the '70s. From their very beginning, their music didn't conform to any commonly held notions about rock & roll -- not even those of the countercultures. Inspired more by 20th century classical music than Chuck Berry, their closest contemporaries were Frank Zappa or possibly the Velvet Underground. Yet their music was more serious and inaccessible than either of those artists. Instead of recording tight pop songs or satire, Can experimented with noise, synthesizers, nontraditional music, cut-and-paste techniques, and, most importantly, electronic music; each album marked a significant step forward from the previous album, investigating new territories that other rock bands weren't interested in exploring.