From initial consultation to termination of treatment, psychologists and other mental health practitioners make a series of crucial decisions to determine the progress and therapy of the patient. These decisions have varied implications such as the clinical course of the patient, the efficacy and efficiency of the treatment, and the cost of the sessions. Thus, the decisions made by mental health professionals need to be accurate and consistent, respecting a series of guidelines that will ultimately benefit the patient. This is the first in a series of guidebooks that is designed to do just that by providing practitioners with some structure in the development of treatment programs. Previous guidelines have been based on consensus panels of experts or on the opinions of membership groups, causing guidelines to be very far off from the findings of empirical research. Here, guidelines are presented in terms of treatment principles rather than in terms of specific treatment models or theories, and they do not favor one theory of psychotherapy over another. Instead, they define strategies and considerations that can be woven into comprehensive treatment programs. The entire series of guidebooks will cover numerous topics, including anxiety disorders, drug abuse, alcohol abuse, and treatment of serious mental disorders. This volume will cover in detail the nature of depression, issues in treatment research, contemporary treatments, and implications for education and training. It is ideal for postgraduates and professionals in the mental health field and is intended to provide important background on treatment of non-bipolar depressive disorders.