When he died in one of rock's string of tragic plane crashes, Otis Redding was only twenty-six, yet already the avatar of a new kind of soul music. The beating heart of Memphis-based Stax Records, he had risen to fame belting out gospel-flecked blues in stage performances that seemed to ignite not only a room but an entire generation. If Berry Gordy's black-owned kingdom in Motown showed the way in soul music, Redding made his own way, going where...