A rare psychotic disorder in which the patient suffers from the delusion of seeing a “double” who looks, talks, dresses, and acts exactly like himself. (The term means “view one’s self.”)The double usually appears suddenly and in colorless form, as in a dream. In spite of the strange nature of the experience, the patient is more likely to react with indifference than with amazement. In some cases the double appears only once, lasting for a few seconds; in others it appears repeatedly, generally in the evening; in still others, the experience always follows disturbing incidents.The term autoscopy was applied by Schilder (1950) to the process of projecting one’s own body-image into the outside world—for example, a crippled person sees a crippled individual. The symptom is most often reported by patients suffering from migraine and epilepsy, though it occasionally occurs in schizophrenic and depressive reactions. Arieti and Meth (1959) suggest that it may be remotely related to such phenomena as eidetic imagery and imaginary companions in children, but that it bears a closer relation to “those conditions in which a psychological picture is superimposed on an original organic condition, such as symptomatic epilepsy, cases of phantom limb, duplication of parts of the body, and denial of illness.” However, no satisfactory explanation for the symptom has yet been found.