Essays, interviews, and projects that consider the notion of medium and the possibilities for its productive use (and misuse) by architects. Since the arrival of radio and television in the twentieth century, understandings of space have become visibly intertwined with what is commonly referred to as the media. But what is a medium? Dictionaries define “medium” as something in the middle, or, a means of conveyance, and this elemental understanding of medium has nourished early conversations of networks and cybernetics, as well as recent media theory. Yet today, midcentury architectural fictions and fantasies are reality—nomadic devices connect people, rooms, buildings, and cities to vast networks of data, capital, and energy; media are palpably enmeshed in the concrete built environment surrounding us. This volume of Perspecta—the oldest and most distinguished student-edited architectural journal in America—takes a broad view of medium to take stock of and unpack unexpected relationships. The study of medium is transscalar and transhistorical. Therefore, media are part of a continuum, and architecture is inseparable from medium. For this reason, Perspecta 51 does not focus exclusively on the “new media” of today or predictions about the future; instead, it presents a conversation among varied theories on medium set against a series of architectural case studies. These include articles about about images and digital commons, heating systems and thermostats, sea level rise and flood-monitoring apps, search lights and public space, media walls and megastructures, social media capitals and suburban sprawl, surveillance and library architecture. A chapter on flexibility demonstrates its thesis by being printed (intentionally) upside down. These stories are grounded in the theories of medium design, mediascapes, and media politics. Perspecta 51 provides new histories and fresh responses to the notion of medium that might illuminate possibilities for its productive use (and misuse) by architects. Contributors Shamsher Ali, Nick Axel, åyr, Aleksandr Bierig, Francesco Casetti, Beatriz Colomina, DIS, Keller Easterling, Georgios Eftaxiopoulos, Moritz Gleich, Evangelos Kotsioris, Nashin Mahtani, Reinhold Martin, Shawn Maximo, Christine Shannon Mattern, Marshall McLuhan, Scott McQuire, Ginger Nolan, Shveta Sarda, Jeffrey Schnapp, Dubravka Sekulic, Prasad Shetty, Molly Steenson, Neyran Turan, Etienne Turpin, Christina Varvia, Richard Vijgen