Behavior therapy in groups — Literature of behavior therapy in groups is reviewed. Different forms and possible effects of group treatments are mentioned. A distinction is made between groups characterised by the communication from the group-therapist to each of the group-members (co-action-behavior-therapy-groups) and groups in which communication between the groupmembers is an important part of the procedure (interaction- behavior-therapy-groups). The Jatter groups involve mostly social behavior change programs.