This classic handbook provides scientific assessment of the efficacy of the most popular psychotherapeutic orientations to promote the use of evidence-based interventions to affect behavioral change and positive client outcomes. Thoroughly updated and revised, the Sixth Edition keeps pace with the rapid changes that are taking place in the field, such as new findings made possible by neuroimaging and gene research, and includes new chapters on psychotherapy process-outcome research, psychodynamic approaches, and training and supervision.