Middle English literature is intimately concerned with sleep and the spaces in which it takes place. These concerns about sleep, and the intersecting medical and moral discourses with which they engage, have been overlooked by studies more interested in what sleep can enable (dreams and dream poetry) or what it can stand in for or supersede (sex). In the medieval English imagination, sleep is an embodied and culturally determined act. It is both performed and interpreted by characters and contemporaries and is both subject to a particular habitus and understood through particular hermeneutic lenses. This book argues that sleep mediates thematic concerns and questions in ways that have ethical, affective and oneiric implications for the medieval English cultural imagination. At the same time, it offers important contributions to understanding different Middle English genres: romance, dream vision, drama and fabliau.