This manual provides a compact, comprehensive, and critical insight into the theory and practice as well as the application areas of modern Gestalt therapy. The book begins with a depiction of the eventful and dynamic history of Gestalt therapy. Another section deals with the theoretical, philosophical, sociological, and psychological foundations, as well as the core concepts and principles of practice in Gestalt therapy. Furthermore, it presents the influences of various therapeutic directions on Gestalt therapy, along with Gestalt therapeutic methods and techniques. A substantial part of the volume focuses on Gestalt therapeutic diagnostics and the use of Gestalt therapy for various disorders. The application of Gestalt therapy with specific client groups and in specialized fields of work is another key focus.