This text examines the five theoretical approaches to psychotherapy that have been most significant in helping psychotherapists understand and treat their clients. These theories have not been static but have continued to evolve. The authors lay out the major tenets in several enduring theories of psychotherapy, discuss the ideas of the authors who have expanded them, and describe the evolution of these concepts over time. The number of theories is kept to a minimum in order to focus on those that are important historically and that continue to be central in guiding research and practice today. Rather than present the field as a list of discrete therapeutic approaches, the contributors have sought deeper commonalities that unite closely related theories of therapy. Thus, the chapter on psychoanalysis includes a discussion of classical Freudian theory, ego psychology, interpersonal theory, object relations theory, and self psychology. That on behavioural and cognitive theories of therapy encompasses behavioural, neobehavioural, cognitive and cognitive-behavioural outlooks. The chapter on humanistic therapies incorporates client-centred, gestalt, and existential streams, and that on family therapy theories brings together strategic, systemic and structural approaches. A final chapter on integrative theories embraces theoretical integration, common factors, and technical eclecticism as routes to rapprochement among the therapies. The editor's introductory chapter presents the broader cultural and social context of the field and includes a critical review of recent work in the areas of brief therapy, modernist versus postmodernist outlooks on therapy, psychotherapy versus psychopharmacology in the treatment of depression, the controversy over empirically validated treatments, and the current movement to managed care.