The American boardinghouse once provided basic domestic shelter and constituted a uniquely modern world view for the first true generation of U.S. city-dwellers. Thomas Butler Gunn’s classic 1857 account of urban habitation, The Physiology of New York Boarding-Houses, explores the process by which boardinghouse life was translated into a lively urban vernacular. Intimate in its confessional tone, comprehensive in its detail, disarmingly penetrating despite (or perhaps because of) its self-deprecating wit, Physiology is at once an essential introduction to a “lost” world of boarding, even as it comprises an early, engaging, and sophisticated analysis of America’s “urban turn” during the decades leading up to the Civil War. In his introduction, David Faflik considers what made Gunn’s book a compelling read in the past and how today it can elucidate our understanding of the formation and evolution of urban American life and letters.