The Family System Test (FAST) was developed at Stanford and the University of Zurich for use with both individuals and families. It is a figural technique, derived from clinical practice, for representing emotional bonds (cohesion) and hierarchical structures in the family or similar social systems. The FAST, which can be used quantitatively or qualitatively, is based on the structural-systemic theory of families. It is assumed that healthy families have a balanced relationship structure (cohesive and with a balanced hierarchy), clear generation borders, and a flexible organization. The FAST can be used as an individual or group test in research and clinical practice for: analysis of family structure; diagnosis of biopsychosocial problems; planning and evaluation of preventive and therapeutic interventions. The FAST is very economical compared with other instruments which provide similar information. Another advantage of the FAST lies in its ability to trigger a process of reflection on family relations among respondents, thus facilitating diagnosis and therapy. A first evaluation is possible right after completion of the representations. For example, it is possible to determine structural characteristics such as clarity of generational boundaries without any prior calculations. A review of the follow-up interviews and the spontaneous comments of the family members permits ad hoc individual and family-oriented systemic hypotheses. Test materials include a board and various schematic figures. Takes only 5-10 minutes for individuals, 10-30 minutes for groups. Language independent and highly effective.