Although it is commonly thought that incest has been taboo throughout history, nineteenth-century Americans evinced a great cultural anxiety that the prohibition was failing. Theologians debated the meaning and limits of biblical proscription, while jurists abandoned such injunctions and invented a new prohibition organized around the nuclear family. Novelists crafted fictional tales of accidental incest resulting from the severed ties between public and private life, while antislavery writers lamented the ramifications of breaking apart enslaved families. Phrenologists and physiologists...