'Public engagement with science' has become a 'buzzword' reflecting a concern about the widening gap between science and society and efforts to bridge this gap. This study is a comprehensive analysis of the development of the 'engagement' rhetoric in the pertinent academic literature on science communication and in science policy documents. By way of a content analysis of articles published in three leading science communication journals and a selection of science policy documents from the United Kingdom (UK), the United States of America (USA), the European Union (EU), and South Africa (SA), the variety of motives underlying this rhetoric, as well as the impact it has on science policies, are analyzed. The analysis of the science communication journals reveals an increasingly vague and inclusive definition of 'engagement' as well as of the 'public' being addressed, and a diverse range of motives driving the rhetoric. Similar observations can be made about the science policy documents. This study corroborates an earlier diagnosis that rhetoric is running ahead of practice and suggests that communication and engagement with clearly defined stakeholder groups about specific problems and the pertinent scientific knowledge will be a more successful manner of 'engagement'.