Anorexia nervosa dramatically demonstrates the inseparability of mind and body and is a classic example of a psychosomatic disorder. It is primarily a psychic and secondarily a somatic disturbance. Inasmuch as the personality reaction of the individual suffering from anorexia nervosa more nearly conforms to compulsion neurosis than that of any other psychiatric disorder and, in addition, has cachexia rather than anorexia as a leading symptom, it is suggested that the illness would be more accurately termed compulsion neurosis with cachexia. Although definitive data as to etiology are not available, evidence presented indicates that constitutional defect probably predisposes to the illness, which becomes manifest at puberty or shortly thereafter because of severe and deep psychological conflicts centering in the family constellation. The dynamics of these conflicts are discussed and the conclusion drawn that the patient's basic difficulty lies in her more intimate interpersonal relationships. Adequate physiological and psychological treatment, described in detail, offers a reasonably good prognosis, although the tendency to relapse is great.