Individual cases of adult incestuous abuse have surfaced repeatedly in the lay and professional literature of the past 1.5 centuries without it occasioning systematic investigation, such as the reporting of a case series of individuals subjected to such extreme abuse. Yet substantial numbers of patients with dissociative identity disorder at the time of presentation report incestuous abuse continuing into the adult years, and for many the abuse is ongoing. Data relating to a series of 10 such incestuously abused women are presented. Suicide and murder occurred within the 1st- or 2nd-degree relatives of these women at a high frequency. All 10 had been sexually abused by various groupings of individuals connected to their fathers.