Although opinion leadership has been the subject of numerous studies, in areas ranging from politics to fashion and in many societies and cultures, The Influentials represents the first systematic analysis of the concept. It offers a multidisciplinary presentation of the definitions, typologies, methods, and findings of opinion leadership, from its early formulation, through the emergence of the first empirical evidence, to the most recent research. Weimann examines opinion leadership and personal influence in a number of areas, including marketing, public opinion and elections, education, fashion, science, agriculture, and health care. He also examines the growing criticism of the model based on theoretical and empirical weaknesses of the original concept and evaluates for the first time modifications that have emerged, including a new measure (the PS Scale) and its testing and application. The final chapters for the first time link opinion leadership with the important theoretical and research tradition of agenda setting.