Most historiographers of psychotherapy point to Eysenck's (1952) formative critique of the field as a significant rallying call to psychotherapy researchers and practitioners to demonstrate the effectiveness of psychotherapy over and above various estimates of natural recovery or so-called spontaneous remission (Bergin & Garfield, 1994; Nathan & Gorman, 1998; Roth & Fonagy, 1996). Although the data and methods employed by Eysenck were brought into question by several researchers (cf. Bergin, 1971), the debate over Eysenck's claims has persisted over the years (Rachman & Wilson, 1980), and in recent years various groups have brought increased pressure upon psychotherapists to demonstrate that what they do actually works. Such pressures have come from Health Maintenance Organizations, insurance companies, consumer activist groups, and from practitioners and researchers within the field. All of these forces continue to converge on two prominent questions: 1. "Is psychotherapy effective?" and, if so 2. "Are some forms of psychotherapy more effective than others for particular kinds of problems and disorders?" In an attempt to provide some answers to the above questions, the purpose of this Special Issue of the Journal of Cognitive Psychotherapy is to review and disseminate the results of empirically validated treatments of cognitive therapy for particular psychological disorders. In this introductory article we will provide a brief historical overview of research on the effectiveness of psychotherapy in the aftermath of Eysenck's (1952) challenge, discuss some of the criticisms of empirically validated treatments, and finally, provide a brief sketch of the contributors to this Special Issue. THE AFTERMATH OF EYSENCK Following Eysenck's (1952) critique of the effectiveness of psychotherapy, understandably, many people within the field became incensed. However, Eysenck persuaded others that the field of psychotherapy could not live up to its claims of being an effective treatment for psychological disorders. Indeed, those who disagreed with Eysenck believed that his claim took on the stature of a myth (Smith & Glass, 1977). Eysenck (1969) compiled his research results 17 years later and published a book in which he came to the same conclusion as his original work. Hence, a debate within the field emerged with those who were pro and those who were anti-Eysenck. Consequently, for a period of approximately 20 years, Eysenck had effectively challenged the field of psychotherapy to support its claims. Researchers and practitioners did not begin to authoritatively respond to Eysenck (1952) until the 1970s. Bergin (1971), for example, explicated some of the methodological flaws in the Eysenck study. Smith and Glass (1977) provided evidence of psychotherapy's effectiveness through the use of meta-analysis. The organizers of the third edition of the Diagnostic and Statistical Manual of Mental Disorders-DSM-lll (American Psychological Association [APA], 1980) sought to solidify the descriptions and discussions of psychological disorders with more empirical data. The organizers and team researchers of the DSM-III hoped the manual could provide a standardized diagnostic system for use in outcome studies (Nathan & Gorman, 1998). Not all researchers and practitioners were convinced, however, that the responses during the decade of the 1970s had adequately countered Eysenck's (1952, 1969) claims. Rachman (1971), for example, analyzed psychotherapy research results and agreed with Eysenck. In a follow-up volume, Rachman and Wilson (1980) were somewhat more optimistic, but guarded, about the effectiveness of psychotherapy. Indeed, Rachman and Wilson provided a counter criticism of Bergin's (1971) critique of Eysenck. Consequently, at the end of the 1970s, researchers and practitioners within the field still demonstrated doubts concerning the benefits of psychotherapy. In 1986, the American Psychologist published a special issue on outcome research in psychotherapy. …