During the past two decades, psychiatric treatment has covered a wide range of procedures, extending from a psychological and social milieu to pharmacological, electrical, and neurosurgical methods. In this symposium on psychiatric treatment, a concerted effort has been made by the contributors to evaluate the effectiveness of various therapeutic modalities. Dealing with individual and group therapeutic procedures and with electrophysiological, pharmacological, and neurosurgical methods, the symposium presents some of the advantages, weaknesses, and omissions in current psychiatric therapy. In summary, the papers indicate that the therapist should be cautious in advancing claims for the exclusive effectiveness of any single treatment or for any single factor influencing treatment in psychiatric practice, for apparently about one-third of patients fail to respond to treatment, one-third get well while under treatment, and one-third are more or less influenced by treatment. This volume should serve to stimulate scientifically critical studies in an important field.