The conceptual clustering of numerous concepts from family therapy and other social science fields reveals two significant dimensions of family behavior, cohesion and adaptability. These two dimensions are placed into a circumplex model that is used to identify 16 types of marital and family systems. The model proposes that a balanced level of both cohesion and adaptability is the most functional to marital and family development. It postulates the need for a balance on the cohesion dimension between too much closeness (which leads to enmeshed systems) and too little closeness (which leads to disengaged systems). There also needs to be a balance on the adaptability dimension between too much change (which leads to chaotic systems) and too little change (which leads to rigid systems). The model was developed as a tool for clinical diagnosis and for specifying treatment goals with couples and families.