Cognitive analytic therapy (CAT) is growing rapidly in the extent of its application in clinical situations and in the development of new theoretical ideas and therapeutic methods. Using case histories and accounts of the application of CAT to particular patient groups, this study also describes the application of CAT's basic approach, devised for individual therapy, to couples and groups. CAT is a unique approach but its derivation from, and links with, other psychotherapy methods and theories continues to be addressed. The relation of CAT to group therapy, cognitive therapy and systems theory approaches are considered by practitioners trained in these fields. Finally, training and supervision are considered in ways which have implications for others concerned with teaching psychotherapy.