Medicine man and Sun Dance chief Thomas Yellowtail is a pivotal figure in Crow tribal life. As a youth he lived in the presence of old warriors, hunters, and medicine men who knew the freedom and sacred ways of pre-reservation life. As the principal figure in the Crow-Shoshone Sun Dance religion, Yellowtail has preserved traditional values in the face of the constantly encroaching, diametrically opposed values of materialistic modern socity. Through his life story and description of the Sun Dance religion we can reexamine the premises and orientations of both cultures.