This dissertation explores the emergence of the suntanned white body in the United States between the World Wars and its dual significance to modernism and the eugenics movement. The suntan serves as a revealing lens for examining the nexus of health, class, gender, and race in early American modernist art and visual culture. Rather paradoxically, as Euro-Americans were trying to preserve certain racial boundaries through eugenics, they also experimented with their own skin color in unprecedented ways. Yet through the popular practice of suntanning, Euro-Americans often transgressed the very racial color lines they sought to maintain. Suntanning---a physical transformation whose most visceral form is the visual---has yet to be critically examined as a subject of art history. This study considers the nineteenth-century medical origins of suntanning as heliotherapy, modern notions of the skin as surface in the consumer culture of the 1920s and '30s, and the primitivist impulse of early American modernist artists in their appropriation of Native American cultural references as well as skin tone. I examine a broad spectrum of visual material ranging from travel, fashion, and cosmetic advertisements to Alfred Stieglitz's photographic portraits of a suntanned Georgia O'Keeffe "playing Indian." I also assert that suntanning is a visual phenomenon in and of itself, a performative process by which skin changes color and texture and becomes a natural canvas. The tanned white body, therefore, serves as a floating signifier suggesting everything from eugenic health to primitivist desire. This dissertation adds richer dimension to our understanding of early American modernism by exposing the colored side of whiteness.