Systemic psychiatry does not view mental disorders merely as illnesses but understands them, in the context of the respective social environment, as attempts to solve problematic life situations. With this resource-oriented perspective on the meaning and function of mental illnesses, it moves away from the deficit-oriented approach of traditional psychiatry. Gerhard Dieter Ruf presents the foundations and principles of systemic psychiatry in this compact introduction. He introduces diagnosis-specific psychosocial patterns and corresponding intervention possibilities based on the most important psychiatric disorders, illustrating them with case examples. It becomes clear that systemic psychiatry can fundamentally contribute to changing the symptomatology even in disorders that are otherwise considered chronic illnesses with poor prognosis.