Psychotherapy is a $2.5 billion business in the United States, but no one can answer the basic question of how therapy works, and no method has emerged for determining what makes therapy successful for some but not for others. This study proposes much-needed answers to the puzzling questions of what therapists actually do when they are effective. The authors of the book offer a mode of evaluation that focuses not on a particular school of therapy but on the relationship between therapist and patient. Their approach, the Harvard Psychotherapy Coding Method, begins with the assumption that good therapeutic relationships are far from intuitive. Successful relationships follow a pattern of behaviours that can be identified and quantified, as the authors demonstrate through clinical research and videotaped psychotherapy sessions. Likewise, positive changes in the patient, observed through client feedback and case studies, can be described operationally; they involve the process of overcoming feelings of detachment, helplessness and rigidity, and becoming more involved, effective, and adaptable. The book explains and grounds these principles in the practice of psychotherapy, making it an accessible and pragmatic work which should give readers a tool for measuring therapeutic effectiveness and further understanding human transformation.