This article explores the discourse of authenticity, which has become central to our understanding of twentieth-century folk music revivals in the United States. The process of musical revival, that is, the self-conscious restoration of musical systems deemed in danger of decline or extinction, has been closely tied to perceptions of exactly what constitutes authentic, or genuine, folk tradition. The term tradition, like authenticity, is a slippery concept based on a self-conscious interpretation and selective editing of the past. The complex mechanism of cultural editing that undergirds the authentication process is fleshed out by focusing on the efforts of one band, the New Lost City Ramblers. During the 1960s the Ramblers introduced northern audiences to what they judged to be authentic southern string-band and bluegrass styles at a time when the urban revival was dominated by popular and artsy interpreters of folk music. The Ramblers' struggles to render accurately southern rural instrumental and singing styles, while maintaining their own distinctive sound, offer insight into the challenges authenticity posed for mid-century folk musicians and their urban audiences, and continues to pose for scholars and cultural workers today.