One night in 1955, Chuck Berry played a show in Mobile, Alabama. His revved-up and revolutionary first hit, “Maybellene” – a joyful story that romped through cars, sex and class – had recently taken Berry from a St. Louis nightclub act to a national star unlike any other. He was tall, limber, smart, sly, incredibly inventive, and animated onstage in ways that helped flex his musicianship rather than detract from it. Plus, he was handsome and black. These were the early days of rock & roll. What the music seemed to stand for – a youthful refusal to defer to adult authority, a preference for turbulent sounds made from outsider forms like blues, boogie and hillbilly, and a willingness among young whites and blacks to listen to and adopt one another’s…