The focus throughout this second edition is on the 1970's and the impact of mass communication on contemporary society. Analyzing the ways in which communication affects and is, in turn, affected by society, the book examines the social, economic, and intellectual environments in which the media operate. Two intellectual factors which have had the most effect on American media--libertarianism and social responsibility--are explored in detail. The authors take a historical viewpoint in discussing the relationship between government and the media, the effect of economic factors on the structure of the communication industry, and the various roles (informer, interpreter, persuader, and entertainer) performed by the media. For example, the present conflict between the President and the press is seen against a background of the relations between Presidents and the press since the time of Franklin Roosevelt. In describing the audiences of various media, the authors review the sociological factors involved in media choice. They predict the effect of the communication revolution on mass media and on communications patterns. (JY)