Book excerpt: The 1920s and 1930s marked some of the most important developments in the history of the American mass media: the film industry's conversion to synchronous sound, the rise of radio networks and advertising-supported broadcasting, the establishment of a federal regulatory framework, and the birth of a new acoustic commodity in which consumers accessed stories, songs, and other products through multiple media formats. The innovations of this period not only restructured and consolidated corporate mass media interests while shifting the conventions of media consumption. They renegotiated the social functions assigned to mass media forms. In this impeccably researched history, Steve J. Wurtzler grasps the full story of sounds media, proving that the ultimate form technology takes is never predetermined but shaped by conflicting visions of technological possibility in economic, cultural, and political realms.