This review of the research into the agenda-setting function of mass communications posits a structure of the agenda-setting process in order to (1) organize the existing research literature in a coherent fashion and (2) identify the gaps in our existing knowledge of the agenda-setting function of the press. Major sections of the paper discuss the difference between the concept and the theory of agenda-setting, the concept of agenda-setting, measuring the agenda-setting influence, the theory of agenda-setting, research strategies, suggested priorities in further work, and the applicability of the concept to research in other mass communication settings. (AA)