For a long time, it has been known that a good therapeutic relationship predicts the success of psychotherapy at least as well as any specific therapeutic techniques. The question remains which aspects of this relationship are particularly significant and how these can be established across different forms of therapy and in various problem situations. German-speaking and American experts from research and practice address this question in an unprecedentedly comprehensive handbook aimed at all professionals working in various fields with individuals experiencing mental health challenges. The contributions are based on current empirical knowledge and extensive practical experience.