This paper reviews what has been learned about evaluation ultilization during the past 20 years. Evaluation utilization is discussed in terms of what is used, who uses evaluation, when evaluation is used, how evaluation is used, where evaluation is used, and why evaluation is used. It is suggested that the personal factor - the interests and commitments of key people involved in the evaluation - is the most important explanatory variable in evaluation utilization. Ten basic utilization-focused evaluation premises are presented, and it is suggested that the primary direction for further utilization research is to test these premises in an integrated, holistic way in real evaluations. The recent external evaluation of the Caribbean Agricultural Extention Project is described to illustrate a comprehensive test of utilization focused evaluation in a real world project. Five issues that continue to create confusion in the field and that emerge from discussions of the stakeholder assumption and research on the personal factor are discussed. It is concluded that evaluators should act on what is already known about utilization and evaluate those actions rather that do further isolated research on utilization. Preliminary observations on the problems of misutilization are also presented. (BS)