The Social Project: Housing Postwar France demonstrates how several bodies of knowledge – architectural, sociological, technological, and bureaucratic – shaped postwar modernism and the making of contemporary urban France. In less than three decades after WWII, France evolved from a largely rural country with an insufficient and outdated housing stock to a highly modernized urban nation. The book traces how this evolution resulted from an unprecedented upshift in production, ranging from mass housing and community centers to entirely new towns. Overturning the prevailing myth that these built environments are the products of a single utopian blueprint gone awry, it unearths three decades of architectural and social scientific experiments centered on everyday life as a object of modernization and domain of expertise. In no other country did modernism and modernization come together in such an intense way that it shaped both contemporary urbanity and our understanding of the social project of architecture at large. Most literature, both scholarly and popular, reads the resulting environments through the lens of current events and explains the recurring social unrest in some of these now deprived neighborhoods with architectural determinism. My book demonstrates how such determinism is itself part of the making these environments, in which social science and architectural design continually informed each other. This study has implications far beyond France; it offers a methodological reframing of the historical agency of architecture and excavates the unprecedented regime of building and knowledge that shaped the postwar city.