This article focuses on the prison as a gendered organization and examines the consequences for treating the male prisoner as the generic prisoner. In order to simplify security protocols and manage outsiders, prison staff and correctional officers use a "commonsense" approach that draws on long-standing and structurally embedded assumptions about the uncontrollable masculinity of minority men. In a "postracial" and "color-blind" modern America, however, the assumption that prisoners are hyperviolent, hypersexual, and dangerously masculine is applied to all prisoners regardless of race. Drawing on two-and-a-half years of ethnographic fieldwork inside a high-security prison, this article discusses the ways that the assumed dangerous masculinity of prisoners facilitates security protocols and isolates male prisoners from their children and families.