Snare drum backbeat plus electric guitar: the simple formula that launched the rock star, and contemporary teen culture along with it. Today, rock 'n' roll seems to define postwar American culture, especially in its impact abroad. Though its inception is often imagined as sudden and seismic, it was, of course, a gradual and complex transition from boogie-woogie to the stardom of Elvis Presley and Bill Haley. A thorough survey of rock 'n' roll's bloodline...