Before the advent of television in the late 1940s, radio was the most popular mass medium in America. During radio's "Golden Age" from 1929 through the end of World War II, radio's comedy-variety, soap opera, and drama programs were a part of the daily lives of most Americans. Unlike movies, radio brought mass entertainment directly into the home and radio stars like Jack Benny, Gracie Allen, and Orson Welles became familiar presences within the family's private space. For the first time, listeners across the country planned their schedules around the same programs and personalities; for example, movie theaters were forced to pipe in the popular Amos 'n' Andy program in 1929 because so many people did not want to leave their homes and miss hearing it. Radio programs functioned as tools of assimilation for many Americans, defining "American" identities through voices. Radio nationalized ethnic, class, and regional accents...