Cognitive Analytic Therapy (CAT) is a brief, integrative model of psychotherapy originally created and delivered in the health service in the United Kingdom. CAT was developed during the 1960s, 1970s and 1980s by Dr Anthony Ryle. Ryle was originally a GP and so brought a medical perspective to his work. He moved from this role to working as the director of the University of Sussex Health Service before becoming appointed in 1980 as a consultant psychotherapist at St Thomas’s Hospital in London. Ryle’s ideas were taken forward during the 1980s by a group of colleagues who shared a similar passion. He documented concepts for describing beliefs, emotions and actions that people repeat in their interactions with themselves, the world and others. The therapeutic relationship becomes a major ‘vehicle for change’ within therapy as observations are made of the repeating relating patterns that the client brings and new ways of relating are tried out.