The only member of U2 that actually resembles a rock star got his start in the late Seventies as a post-punk amateur with low job security: At one point, his bandmates considered kicking him out, a move encouraged at the recording of U2's first demo by a record executive aghast at Mullen's dodgy timekeeping. He turned things around, however, to become one of the most influential skinsmen in rock. Technologically savvy and surprisingly funky, Mullen keeps U2's grooves pushing forward towards the future — from the martial snare blasts announcing "Sunday Bloody Sunday," to finding the human heartbeat amidst Achtung Baby's clubby electronics. He argued to producer Brian Eno that a click track was a fraction of a beat off of the band — after the drummer left the studio, Eno discovered it was askew by six milliseconds. "The thing is," Eno told The New Yorker, "when we were adjusting it I once had it two milliseconds to the wrong side of the beat, and he said, 'No, you’ve got to come back a bit.' Which I think is absolutely staggering."