So it is too that in the eyes of the world it is dangerous to venture. And why? Because one may lose. But not to venture is shrewd. And yet, by not venturing, it is so dreadfully easy to lose that which it would be diffi cult to lose in even the most venturesome venture, and in any case never so easily, so completely as if it were nothing . . . one's self.-Kierkegaard, Th e Sickness Unto Death (1849)Cognitive behavior therapy (CBT) has now become the dominant force in psychotherapy in much of the world, including North America, the United Kingdom, much of Europe, and increasingly throughout Asia and Latin America. Th e rise of CBT is due to the confl uence of several factors, primary among which is the increased focus on evidence-based practice and associated calls for accountability in the delivery of behavioral health services (Baker, McFall, & Shoham, 2009). Th roughout its history, CBT has been committed to a scientifi c perspective to the study of psychopathology and its treatment. Hundreds of studies have evaluated various cognitive behavioral theories of psychopathology, and hundreds more have assessed the effi cacy of CBT interventions. Th is scientifi c literature has placed CBT in a unique position to dominate the fi eld of psychotherapy.Th is extraordinary growth immediately raises the question: What exactly is CBT? Does the term refer to a specifi c model of psychopathology or psychotherapy? Or perhaps to a domain of treatment, either in terms of targeted processes or pathologies? In fact, the term CBT has become so broad as to defy clear defi nition. Th e Web site of the Association for Advancement of Behavioral and Cognitive Th erapies, the premier multidisciplinary, international organization devoted to CBT, avoids a specifi c defi nition of the term, instead describing the organization's mission as "the advancement of a scientifi c approach to the understanding and amelioration of problems of the human condition." Various theories, principles, models, and techniques fall under the general rubric of CBT, and these approaches have been applied to the full range of human experience, from the assessment and treatment of severe psychopathology and profound developmental delays to primary prevention eff orts to enhancing peak performance among athletes. CBT has become