"High Risk Modernism" demonstrates the importance of the dimension of altitude in shaping modern conceptions of space and time. This study of literary texts and archival material maps out the cultural significance of aviation and mountain landscape during the peak years of Anglo-American modernism, from 1900 to 1940. I argue that current critical studies of modernity and space have overlooked the crucial dimension of altitude, and I seek to restore the conceptual and cultural importance of high spaces to understandings of the intersections of mass culture, literature, technology, fashion, and landscape. "High Risk Modernism" explores the roles of aviator, aviatrix, and alpinist in a recovery of the relationship between altitude and modernity. I am particularly interested in the cultural narrative formed through the period's widespread fascination with altitude, a narrative arc that encompasses the poles of accident and ecstasy involved with aerial travel. I trace this arc through chapters that deal with crashes and disaster, competitions to extend the boundaries of space, fashion and the commodity culture of altitude, and finally the hope for restoration of bodies in the resort culture of the Alps. These chapters demonstrate the high risk posed to the body in journeys to high places, but also tell the story of the seductive appeal of a space that would forever redefine the horizon of modern experience.