The city of Philadelphia, today, is in the midst of revamping its plans for emergency preparedness. For a city of its size, age, and infrastructural complexity, this presents a number of critical challenges. This article examines the last era in which emergency preparedness—in the form of early cold war civil defense—stood at the forefront of the city’s challenges. This article develops a historical case study of Philadelphia’s civil defense efforts against atomic attack in the 1950s, especially in the earliest planning and implementation stages under retired Major General Norman D. Cota. Civil defense failed in Philadelphia, as it did across the nation, and this article considers in detail the role that Cota’s “command- and-control” methods led to this failure.