The use of treatment manuals has produced a revolution in therapeutic research, training, and clinical practice. This revolution has generated fundamental questions about how flexibly the manuals should be followed and about the relationship between the use of specific techniques, the patient engagement in the treatment, and therapeutic change. This book provides new answers to these questions through a comprehensive review of the literature and the examination of the relationship between the patient alliance and therapist adherence, and their effect on depression change. Using data from the National Institute of Mental Health Treatment for Depression Collaborative Research Program (NIMH TDCRP), the findings show that the use of techniques different from those prescribed by the manual can have a positive influence on patient alliance and depression change and that the relational and technical dimensions of psychotherapy are deeply interrelated. This book is of interest to students, researchers and clinicians looking for more effective uses of therapeutic manuals and the reciprocal influence between the technical and the relational dimensions of psychotherapy.