The author hypothesizes that erotomania, or de Clérambault's syndrome, occurs in two forms: the clinically accepted delusional erotomania, in which patients believe that another person is in love with them; and borderline erotomania, in which no delusion is present, yet an extreme disorder of attachment is apparent in the pursuit of, and in the potential for violence toward, the unrequited love object. The author reviews the empirical literature concerning erotomania and then develops an object relations understanding of the disorder, focusing on the presence of narcissistic, hysterical, paranoid, and psychopathic traits in the erotomanic individual.