Who were the first giants of American rock and roll? Which songs and labels and performers drove rock's emergence and explosive growth in the mid-twentieth century? In what ways did the rhythm and blues sound created by African-American composers, singers, and musicians between the world wars become the foundation of early rock and roll? This wide-ranging encyclopedia answers these questions and many more through informative biographical profiles, coverage of noteworthy recordings and performances, and entries on important record labels, concert venues, and related musical genres including blues, folk, gospel, and Western swing.