[Machine Translation] When predicting the near future of the media, there is much to be learned from the history of radio: at the dawn of the 20th century, radio was the latest new medium in the field of communication using radio waves. From there, radio broadcasting was gradually organized as an industry and established as a mass medium, and the programs that were constantly broadcasted on a daily basis shaped the culture of people's lives. This book examines the tectonic shifts experienced by the media and various aspects of culture in modern society through the development of radio in the United States from the early to mid-20th century. This is the long-awaited paperback edition of a classic book written on the eve of the advent of the Internet, with an additional new chapter.