THE STUDY which we are reporting here represents one attempt to search out the essentials of the psychotherapy process by empirical means, to penetrate the complex issue of therapy evaluation, and to elucidate the criteria which patients and therapists use as they weigh, judge, and integrate their therapy experiences. Our approach to this problem takes advantage of a natural rating scale we have observed spontaneously used by therapists and patients alike: the immediate postsession evaluation of the therapy hour. Each therapy session forms a concrete unit of the psychotherapeutic experience. As it is completed, the hour looms in one's immediate feelings and reflections as "good" or "poor," as "really great" or "awful," or as just another "so-so" session. Of what significance is this reaction? To what use, if any, may it be put in attempting to comprehend the essential nature of psychotherapy? Most obviously, this reaction