Sigmund Schlomo Freud (6 May 1856 - 23 September 1939), was an Austrian neurologist who founded the psychoanalytic school of psychology. Freud is best known for his theories of the unconscious mind and the defense mechanism of repression and for creating the clinical practice of psychoanalysis for curing psychopathology through dialogue between a patient and a psychoanalyst. Freud is also renowned for his redefinition of sexual desire as the primary motivational energy of human life, as well as his therapeutic techniques, including the use of free association, his theory of transference in the therapeutic relationship, and the interpretation of dreams as sources of insight into unconscious desires. PSYCHOSOMATIC MEDICINE is now part of the larger field of behavioral medicine. These are disturbances of visceral function, secondary to chronic attitude and long continued reaction to stress. Although failure to diagnose a case medically might be due to a doctor's lack of knowledge or to a faulty laboratory test, in a large group of cases psychological rather than physiological factors are responsible for the symptoms.