In the early 1890s Freud expressed the belief that many cases of hysteria had a basis in childhood incest. Later he expressed a different view, emphasizing childhood fantasies of sexual intimacies with a parent that never actually took place. Freud never totally repudiated his original seduction theory, however, maintaining to the end of his life that at least some cases of actual incest occurred and that these instances underlay certain types of psychopathology. In our era we have become aware that incest is frequently a forerunner of subsequent borderline disorders, especially in women hospitalized with borderline personality disorder (B.P.D.). All the clinical manifestations of B.P.D. can be related to the prior incest experiences.