Gestalt therapy is currently the psychotherapy method with the highest effect sizes worldwide. The handbook will finally ensure that gestalt therapy receives the recognition it deserves in the German-speaking world, benefiting patients, the statutory health insurance system, and the overall health policy situation. The handbook represents a novelty in gestalt therapeutic literature in several respects. For the first time, it brings together specialists from different generations and over 20 countries who represent the current state of international research and address numerous existing gaps in gestalt therapy. Fundamental theoretical principles for clinical practice, unique perspectives, therapy in specific life situations, and clinical applications for specific forms of suffering are presented in 33 articles, each complemented by commentary from another author. Additionally, for the first time, the topic of psychopathology is consistently examined from a gestalt therapeutic and relational perspective. The handbook articulates a specifically gestalt therapeutic view on understanding psychopathology: psychopathology as a co-created field phenomenon that arises at the contact boundary and can be transformed in the contact process. The German version of this international project has been specifically adapted and supplemented to reflect the situation, research, and literature in the German-speaking world.