There has been a renewed interest in the last ten years in the underpinnings - theoretical, philosophical, and historical - of the Gestalt approach. Often in the past, these have been lost in oversimplified versions of the therapy. The author's aim in his writings has been to provide a full and coherent account of Gestalt theory, and to emphasise our links to our therapeutic and philosophical heritage, particularly psychoanalysis and existentialism. His theme is a field-relational theory of self as the centrepiece of the approach, and how this has been placed within a structure that is still recognisably psychoanalytic. In this approach, self is understood as meaningful only in relation to what is taken as other, and how that other is contacted. The formation of a relatively coherent self-concept is a task, not a given, and can be problematic as well as helpful (when it no longer supports the person's life-situation) Thus therapy is not an attunement to a self inherent in the client, but an exploration of contacting and awareness; and the therapist's stance can never truly be seen as neutral. Many of these ideas have found their way in some form into other therapeutic approaches (Intersubjectivity Theory, Dialectical Behaviour Therapy), and the actual relationship between therapist and client is acknowledged as highly significant. However, this has usually happened without the underpinning of a systematic field-relational approach to psychotherapy, and Gestalt Therapy, which has one, has for historical reasons not been in a position to engage with these developments. Fortunately this is now changing, and it is hoped that this work will help that development.