This book tells two closely-related stories: first, how the digital cloud grew out of much older networks, such as television, the railroad, and the sewer system; and second, how the cloud grafts digital technologies onto older ways of exerting power over a population (such as state violence and torture). With the latest revelations about National Security Agency surveillance, readers are increasingly aware that the cloud represents politically contested terrain. While typical responses to this debate invoke technological and legal solutions, such as do-not-track software or a new law, this book takes an alternate approach. The perspective of media studies, and, more generally, understanding the cloud as a cultural fantasy, situates these vital debates within a wider American political and social context. It allows readers to understand why discussions of threats to the ‘free’ Internet, such as spam and hackers, often invoke the specter of foreignness (e.g. China, Iran, Nigeria); why Cold War rhetoric has increasingly informed digital threats, as in the New York Times’s invention of the phrase “mutually assured cyberdestruction”; and even why the NSA’s facilities for decrypting intercepted messages are often identical to those used by archivists trying to place digital media into cold storage. By locating the materiality of the cloud within the discourses of security and participation in postwar America, A Prehistory of the Cloud offers a set of new tools for rethinking today’s digital environment.