Interpersonal issues such as loneliness, intimacy, conflict, communication, assertion, aggression, and insecurity form the bulk of any clinician's concerns, yet the therapies offered to clients are mainly individual. The study of interpersonal relationships provides a necessary link between the person and the mainly social environment in which he lives. There are six major ideas in the conception of interpersonal relationships. The first main idea is interdependence, the notion that a relationship exists when the thoughts, feelings, and behaviors of each person are influenced by the behavior of the other. Second is the idea of recurrent interaction pattern. The form of any continuing relationship is defined by the pattern of recurrent interaction that goes on between or among the people in the relationship. Third is the concept of interaction episode. Episodes are the basic materials that make up relationships, and provide the basic data required for the study of relationships. A fourth concept concerns the linkage of personal characteristics with the courses of interactions and relationships. A fifth concept is the connection between person and environment; the idea that environmental conditions influence interactions and interactions influence the surrounding environment. The final general concept is the assumption of circular causality in examining linkages among personal dispositions, interpersonal relationships, and societal conditions. (NB)