© 2019 Taylor and Francis. Understanding persuasion is fundamental to understanding human communication in general. Persuasion theories, techniques, and research results often guide research and practice in a variety of applied communication areas. This chapter examines definitional issues related to persuasion theory and research. Various approaches to persuasion research are introduced, and variables central to much modern and contemporary persuasion research are examined. In addition, a sample study is described and critiqued.