The study of mass communications is a broad, multidisciplinary field to which sociology has made major contributions. Some of these contributions have been reviewed in earlier works by Riley & Riley (1959), Larsen (1964), Janowitz (1968), McQuail (1969), Davison & Yu (1974), & Ball-Rokeach (1975), and Wright (1975a). Several chapters in Annual Review of Psychology, although not explicitly sociological in orientation, report on communication studies of sociological relevance. Schramm(1962) reviews the social psychology of mass communication from 1955 through 1961. Tannenbanm & Greenberg (1967) update that review through 1966, and W. Weiss (1971) brings it up to 1970. Lumsdaine & May (1965) focus on educational media, a topic beyond the scope of this review. (For an account of recent developments in media of instruction, see Schramm 1977.) And a recent review by Liebert & Schwartzberg (1977), which focuses the effects of the mass media, also presents data on patterns of media use, media content, and transmission of information and cultivation of beliefs-- all of which are topics of sociological concern. Current statistics on the distribution, structure, and uses of mass media are available in Frey (1973) and in a recent comprehensive review and guide American communication industry trends by Sterling & Haight (1978). In addition, the reader can find useful sociological materials on the mass media in the Handbook of Communication(Pool et al. 1973) and in Communication Research---A Half-Century Appraisal (Lerner & Nelson 1977). Here we review sociological developments in five areas of mass communications research, concentrating on the period from 1972 through mid- 1978 but also including some earlier research. First, we examine studies of mass communicators, media organizations, and the processes by which mass communications are produced. These studies relate to sociological interests in occupations and professions, complex organizations, and the phenomenon of work--placing the communicator in the context of the social system, a sociological development in communications research foreseen by Riley & Riley (1959) two decades ago. Second, we consider research on mass media audiences, especially research oriented toward interests in social differentiation and in the social psychology of media uses and gratifications. Third, we review studies that relate interpersonal communication and mass communication - opinion leadership, communication networks, and diffusion of news. Fourth, we consider studies of mass media content that touch upon changing social norms and upon the public presentation of social roles. Finally, we review recent research on mass communication effects, especially studies attempting to determine the media's effects on public beliefs, knowledge, and concepts of social reality, but also those considering the media's roles in socialization and social change.