The author reviews psychoanalytic viewpoints on dissociation and dissociative identity disorder (DID), the controversial condition previously known as multiple personality. He expands his own contributions to the literature over the last fifteen years, incorporating the burgeoning data from research on disturbances of attachment as precursors to dissociation. Utilizing clinical material, he then contrasts DID with trauma and dissociation in adulthood as well as with schizophrenia. He contends that the complexity and myriad manifestations of this condition warrant deeper psychoanalytic exploration to help elucidate not only its true nature, but also to further our understanding of all psychopathology.