In Riotous Flesh: Women, Physiology, and the Solitary Vice in Nineteenth-Century America (University of Chicago Press, 2015), historian April R. Haynes “tells the story of how masturbation became a reviled sexual act charged with political meaning in the United States” during the antebellum period (4). While masturbation, or “onanism,” had long been understood as a problematic sexual practice, prior to the 1830s Americans were largely unresponsive to calls for widespread moral panic. Yet by the late nineteenth century, masturbation — “the solitary vice” — was commonly understood as a dangerous habit. Social reformers and the medical establishment alike held it responsible for a wide range of social and personal ills. At the dawn of the twentieth century it had become a cornerstone of white, progressive America’s policing of bodies considered deviant.