[Cognitive therapy: foundations, conceptual models, applications and research]. 
There is growing interest in the cognitive model of psychotherapy stimulated by an extensive body of research findings demonstrating its effectiveness for a varied set of psychiatric disorders and medical conditions.  This review article aims to give an overview of the historical and philosophical background to contemporary cognitive and cognitive-behavioral approaches to psychotherapy, pointing out similarities across and differences between them.  A presentation of the cognitive model as designed by Aaron Beck, and some of the cognitive and behavioral techniques used in emotional disorders will be discussed.  Outcome studies and meta-analyses contemplating the efficacy of cognitive and cognitive-behavioral therapies in various psychological and medical conditions will be briefly depicted.  Through review of articles and textbooks, especially the works of Aaron Beck from which this review article has heavily borrowed, the origins and foundations of the cognitive-behavioral approaches to the treatment of psychiatric and medical conditions are described.  Through Medline, the search of randomized controlled trials and meta-analyses has pointed out the evidence-based efficacy of this psychotherapeutic approach.  Cognitive-behavioral therapies in general and Beckian cognitive therapy in particular hold a theoretical foundation and a varied set of techniques, whose evidence-based efficacy was demonstrated for the treatment of diverse mental and physical conditions.