This paper reviews research on supervision in counselor training. The author approaches supervision in counselor training as a continuum. At one end are those who see supervision primarily as a didactic activity and at the other extreme are those that stress the experiential, "counseling" approach to supervisory role. The two approaches demand very different behaviors from the supervisor--the first, lecturing explaining, etc.; the second, listening, understanding, reflecting. Approaches near the middle of the continuum utilize both didactic and experiential skills. There is little research on what comprises ideal supervisory behavior, not on what supervisors themselves view as ideal supervision. Several studies looked at what supervisors actually did, and their results are inconsistent. Research using behavioral analyses of supervisor activities is reported, and the general conclusion is that not enough is known as yet about supervisor behavior nor about the factors that make for successful supervision. (NG)