This chapter extends the study of security from political science, sociology, and cultural anthropology to literary studies. To this end, the chapter puts into conversation Charles Brockden Brown’s urban gothic novel Arthur Mervyn (1799/1800) and the theorization of security offered by Michel Foucault. Brown’s fictional exploration of security and Foucault’s historico-theoretical approach both focus on political responses to infectious disease in urban spaces. While there are striking similarities between their perspectives, this chapter does not read Brown with Foucault. Rather, it shows how Brown’s literary treatment of the yellow fever epidemic that raged through Philadelphia in 1793 differs from what Foucault called the “security dispositif.” Brown proposes that the embrace of uncertainty in responding to the epidemic will have positive effects on the moral fiber of the republic. His republican security imaginary is irreducible to the Foucauldian program of critiquing the biopolitical regulation of individual and collective life, not least because Foucault’s target is a political order that is liberal rather than republican.