Setting the Agenda describes the mass media's significant and sometimes controversial role in determining which topics are at the centre of public attention and action. Although Walter Lippman captured the essence of the media's powerful influence early in the last century with his phrase, "the world outside and the pictures in our heads," a detailed, empirical elaboration of this agenda-setting role of the mass media did not begin until the final quarter of the 20th century. In this comprehensive book, Maxwell McCombs, one of the founding fathers of agenda-setting tradition of research, synthesizes the hundreds of scientific studies carried out on this central role of the mass media in the shaping of public opinion. Across the world, the mass media strongly influences what the pictures of public affairs "in our heads" are about. The mass media also influences the very details of those pictures. In addition to describing this media influence on what we think about and how we think about it, Setting the Agenda also discusses the sources of these media agendas, the psychological explanation for their impact on the public agenda, and the subsequent consequences for attitudes, opinions and behaviour.