Cognitive therapy is one of the newest and most promising developments in the psychotherapeutic field. Following the basic proposals of Beck, Ellis, and Frankl, an increasing amount of work is being done which shows a strong interest by behavior therapists in cognitive strategies. An in creasing number of outcome studies show that cognitive methods are effective in many disorders, and it can be predicted that they will have a growing part to play in the practice of psychological therapies. In spite of this, the development is only in its beginnings. Especially from a theoretical standpoint, many of the proposed techniques lack a sufficient foundation, and the implications of important results from dif ferent areas of psychology for providing a theoretical basis for cognitive intervention have not yet been sufficiently recognized. To investigate these developments is the main purpose of this book. The intention of the authors is not to give a summary of the present status of cognitive therapy but to try to show its possibilities for future development. A number of areas of psychological research have been selected as being the most important for future development of cognitive therapeutic techniques: the genetic theory of Piaget, the investigations of attitude theory, attribution theory, and psychological action theory, and the psy chology of problem-solving. After a description of the latest developments in these areas, the authors attempt to extract the theoretical implications for cognitive ther apy and, on this basis, to make a few initial proposals for practice.