Mark Miller is Associate Professor of English at the University of Chicago. He is the author of Philosophical Chaucer: Love, Sex, and Agency in the "Canterbury Tales" (2005) and is currently completing a book on ethical and political impossibility in late fourteenth-century English poetry. A version of the first chapter appeared as "Sin and Structure in Piers Plowman: On the Medieval Split Subject," in MLQ 76 (2015), 201–24.