This volume argues the case that public health communication has affected health behavior. It brings together 16 studies of large-scale communication in a variety of substantive health areas–tobacco, drugs, AIDS, family planning, heart disease, childhood disease, highway safety–prepared by the authors who did the original research. These studies show important effects and illustrate the central conditions for success. The book also includes complementary analytic chapters which provide a meta-analysis of published results, some approaches to developing communication interventions, and alternative methods for evaluation of public health communication projects. Including studies based on communication programs in the United States, as well as projects done elsewhere in the world, including Europe, Africa, Asia and Latin America, this book: *offers a broad presentation of the alternative research designs that have been used to evaluate public health communication programs; *includes a great range of approaches from field experiments and natural experiments to simple before-after and complex time series designs, using data gathered from individuals and from archives; and *utilizes an innovative perspective on how to exercise public health communication from a leading and thoughtful practitioner. As such, it is required reading for scholars, students, practitioners, and policymakers in public health, health communication, health psychology, and related areas.