Swiss psychiatrist and writer who applied the principles of existential phenomenology, especially as expressed by Martin Heidegger, to psychotherapy. Diagnosing certain psychic abnormalities (e.g., elation fixation, eccentricity, and mannerism) to be the effect of the patient's distorted self-image and his inadequate relation to the world, he developed a form of psychoanalysis to establish the patient's consciousness of self as a total person, uniquely existing in and communicating with the concrete world as it is. Among his important writings are Grundformen und Erkenntnis menschlichen Daseins (1962; abridged Eng. trans., Being-in-the-world) and Erinnerung an Sigmund Freud (1956; Sigmund Freud: Reminiscences of a Friendship).