Poetry has long been regarded as the least accessible of literary genres. But how much does the obscurity that confounds readers of a poem differ from, say, the slang that seduces listeners of hip-hop? This book examines not only the shared incomprensibilities of poetry and slang, but poetry's genetic relation to the spectacle of underground culture. Charting connections between vernacular poetry, lyric obscurity, and types of social relations—networks of darkened streets in preindustrial cities, the historical underworld of taverns and clubs, the subcultures of the avant-garde—it shows that obscurity in poetry has functioned for hundreds of years as a medium of alternative societies. For example, the book discovers in the submerged tradition of canting poetry and its eccentric genres—thieves' carols, drinking songs, beggars' chants—a genealogy of modern nightlife, but also a visible underworld of social and verbal substance, a demimonde for sale.