This dissertation examines clothing and sartorial cultures from the perspective of existentialist philosophy. Utilizing the works of Sartre and Heidegger, I provide an existential explanation for why clothing arose and how sartorial practices are linked to our uniquely human existential situation. This interdisciplinary work draws from the social sciences, religious studies, archaeology, paleontology, history, fashion studies, literature, film, television, the visual arts, and journalism, as well as philosophy. Beginning with Christian and scientific views of the advent of dress and adornment, I argue that there is a shared intuition about their existential significance. As free conscious beings, our fundamental work is to engage in existential projects, which define us and give meaning to our lives in the face of death. As social beings, we enlist others to help us realize our projects. Entire societies adopt collective existential projects and, like individuals, they develop strategies for dealing with mortality and temporality by embracing change, maintaining the present, or becoming nostalgic. Sartorial practices are a product of these strategies. By examining the dress of ancient Greece, feudal Japan, post-revolutionary China, and the countercultures of the 1960s and '70s, I argue that sartorial practices are inextricably tied to larger existential strategies, including social and political movements. In reviewing cultural ideals and prejudices, I challenge the view that dress and appearance are frivolous. Clothing is never neutral. It is always culturally inscribed and subject to interpretation, which includes judgments about the character, identity, and social role of the wearer. Thus who is doing the gazing and under what constraints such interpretation occurs becomes paramount, particularly since the presentation of the clothed body and the representation of the clothed self intersect with race, class, gender, age, and thus have normative and political implications. I then explore whether a truly authentic engagement with sartorial culture is possible.