This issue of "American Journal of Evaluation" presents commentaries by evaluation leaders, George Grob and Rakesh Mohan, which draw upon their wealth of practical experience to address questions about evaluator advocacy, including What is meant by the word "advocacy"? Should evaluators ever advocate? If so, when and how? What are the payoffs and risks to evaluator advocacy? And perhaps most practically, how can evaluators become more comfortable with an advocacy role? As an introduction to these commentaries, Michael Hendricks broadens the reader's frame of reference about what exactly an evaluator might advocate "for," whether operating in the public, nonprofit, or private sector, domestic, or international. In this article, he discusses the following four levels of advocacy: (1) Advocating for the results of a specific evaluation; (2) Advocating for adequate support to evaluations in general; (3) Advocating for the concept of evaluation; and (4) Advocating for effective and open governance. Hendricks concludes that an essential first step for evaluators is to recognize that these four different levels of advocacy exist and that there are important differences among them. Such differentiation could help evaluators advance their thinking about each level and about evaluator advocacy overall.