Poetry has long been regarded as the least accessible of literary genres. But how much does the obscurity that confounds the reader of a poem differ from, say, the slang or patois that captivates listeners of hip-hop? "Infidel Poetics" examines not only the shared incomprehensibilities of poetry and slang but also poetry's genetic relation to the spectacle of underground culture. Charting connections between lyric obscurity, vernacular speech, and types of social relations - networks of darkened streets in preindustrial cities, the historical underworld of taverns and clubs, and the subcultures of the avant-garde - Daniel Tiffany shows that poetic obscurity has functioned for hundreds of years as a medium of alternative societies. For example, he 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. Ranging from Anglo-Saxon riddles to Emily Dickinson, from the icy logos of Parmenides to the monadology of Leibniz, from Mother Goose to modernism, "Infidel Poetics" offers an exhilarating account of the subversive power of obscurity in word, substance, and deed.