To promote Kraftwerk's 1991 remixed "greatest hits" compilation The Mix, the group's American label, Elektra, came up with an amusing ad: a simulation of the famous one-and-only photo of blues pioneer Robert Johnson, but with his suit filled by a robot's body. The visual pun was witty and eye-catching, but most important, it was accurate. Just as Johnson was the godfather of rock's gritty authenticity and wracked catharsis, Kraftwerk invented the pristine, posthuman pop phuture we now inhabit. The story of techno begins not in early-eighties Detroit, as is so often claimed, but in early-seventies Dusseldorf, where Kraftwerk built their KlingKlang sound factory and churned out pioneering synth-and-drum-machine tracks like "Autobahn," "Trans-Europe Express," and "The Man-Machine."