Through a combination of zealous righteousness and post-punk experimentalism, U2 became one of the most popular rock & roll bands of the '80s. Equally known for their sweeping sound as for their grandiose statements about politics and religion, they were rock & roll crusaders during an era of synthesized pop and heavy metal. The Edge provided the group with a signature sound by creating sweeping sonic landscapes with his heavily processed, echoed guitars. Though the Edge's style wasn't conventional, the rhythm section of Adam Clayton and Larry Mullen, Jr., played the songs as driving hard rock, giving the band a forceful, powerful edge that was designed for arena rock. And their lead singer, Bono, was a frontman who had a knack of grand gestures that played better in arenas than small clubs. It's no accident that footage of Bono parading with a white flag with "Sunday Bloody Sunday" blaring in the background became the defining moment of U2's early career --...