This dissertation is a monograph on the early work of the Hungarian-born architect Yona Friedman (1923-2019). A singular and deeply influential, but little studied, figure in postwar art and architecture, Friedman is best known as an exemplar of megastructuralism. He is also recognized as an important progenitor of “participatory” approaches to art and design and as an advocate of common modes of knowing and making that have been historically devalued by professional training and academic disciplines. This study offers a new interpretation of Friedman’s oeuvre as an explicitly political anti-fascist project, shaped by the Holocaust, that expanded over decades into a comprehensive reimagining of architecture’s role in a democracy. It charts a historical trajectory that begins in Hungary in the 1940s and ends in 1970 with Friedman’s rise to international recognition after he settled permanently in France in 1958. The intervening decade that Friedman spent in Palestine/Israel (1946-1957) is shown to be a critical site of professional and conceptual formation in which Friedman engaged the political stakes of urban planning and began developing a critique of architectural expertise and modernist verities, while himself designing mass housing projects. Drawing on extensive archival research, I introduce vast swaths of previously unknown works, built and unbuilt. From these, I excavate Friedman’s distinctive studio processes, which attempted to visualize experiments with kinetic architecture through an unconventional use of photography, serial reprography, and the materials and technologies of film. Employing a cross-disciplinary methodology that merges the distinct interpretive traditions and historiographies of postwar art history and architecture, as well as oral history and political philosophy, the dissertation corrects errors of reception that have narrowed Friedman's work to utopian “paper architecture.” I show that Friedman’s theories and projects were developed from a continuous attention to the untapped potential of already existent building technologies. Over six chapters, the dissertation traces a linked chain of experiments in low-cost, mass-producible, factory-made architectural systems designed to be easily constructed, moved, and adapted without need for professional expertise, beginning with designs for movable shelter that Friedman developed when he was himself sheltering in a Displaced Persons’ camp in Romania in 1945. I identify as the architectural genesis point of Friedman's work the built environment of the Second World War, from rubble fields, to military engineering, to the prefabricated huts mass-produced for soldiers and later used to house survivors like him. The exigencies of transnational migration and the international challenges of reconstruction are key thematics in Friedman’s work and they structure this dissertation. Ultimately, the dissertation asks Friedman’s questions: What is the political potential of architectural prefabrication? What needs to change in our conception of design to allow people to shape their own environment? What does a democratic urban plan look like? What could an anti-fascist architecture actually achieve? Exploring Friedman’s early attempts to answer these questions, I argue that Friedman's most significant contribution is his positioning of the refugee as the paradigmatic figure at the heart of architecture’s theories and responsibilities.