Mental health evaluation is reviewed as a specialized branch of the field program evaluation. Historical influences on the field, current issues and techniques, and unique role requirements for the mental health evaluator are presented in a detailed review of the literature. Role demands and specific evaluation methods are described in relation to several actual and potential evaluator roles, including information monitor, summative judge of program worth, formative collaborator in program development, and change agent. Techniques reviewed include outcome measurement, goal-attainment scaling, costanalytic procedures, epidemiology, ecological approaches, information systems, systems analysis, and peer review. The adoption of metaevaluation procedures to improve the utility of mental health evaluation efforts is advocated. ¡ , n the past two decades, evaluation of social, educational i medical, and mental health programs has been a rapidly ex-';¡ panding, highly valued enterprise. Some professionals in the field have ' tended to view evaluation as a content-free set of methods for judging the worth of a broad variety of programs. Others have evolved more target-specific methodologies in keeping with the specialized objectives and role requirements for evaluations in particular settings. This paper reviews the development of one branch of the evaluation enterprise, that of applications in mental health settings. The guiding thesis of the presentation is that mental health evaluation is, in a number of