THIS PAPER reports on a study designed to make available basic information about patients treated in psychoanalysis and psychoanalytically oriented psychotherapy, and to record changes that have taken place from the beginning to the end of treatment.1-4 Information was recorded from the written histories of 1,348 patients treated at Columbia University's Psychoanalytic Clinic for Training and Research. These data were put on punch cards and magnetic tape, then analyzed using electronic data-processing techniques. The structure and aims of this study will be presented, along with a description of clinical findings related to changes in the major areas of disturbance. The original discoveries of psychoanalysis and subsequent theoretical formulations and generalizations about analytic techniques have been based primarily upon observations of the individual patient in the therapeutic relationship. Depth studies of individual patients have been the paradigm for analytic research, and it is