Through analyses of the dialectical interaction between literary representation and its material support in a selection of late Middle English poems, this dissertation theorizes and demonstrates a method of reading late medieval textuality as an aesthetic phenomenon that encompasses not only texts—understood as transcendent, transhistorical bodies of discourse—but also the physical artifacts that preserve them. Each of the “odd texts” upon which I focus calls attention, self-reflexively, to a feature of its own material instantiation, in this way extending the boundaries of its poetics to include its physical frame. My analysis of these works follows the contours of medieval books themselves; that is, each chapter considers a poem, or group of poems, that thematizes a progressively larger component of a manuscript book. The study begins, then, with the most elementary component of written things, the alphabet, with an examination of a little-studied genre, the Middle English alphabet poem. By bringing a study of medieval writings about the alphabet to bear upon a consideration of the layout and decoration of these poems in their manuscript contexts, I argue that the alphabetical characters they feature render abstract devotional and didactic themes “graphically” present, functioning variously as jewel-like rosary beads, as red-ink wounds of the crucified body of Christ, or as models for the kind of behavior that would make individuals properly legible within the hierarchy of literacy in fifteenth-century English society. In the following three chapters and an afterword, I describe a similarly diverse array of bibliographic effects—or “marginal subjects”—that emerge along the productive interface between epistles and their pages, in Chaucer's Troilus and Criseyde and in a selection of Middle English verse love epistles; between a text and its commentary, in Gower's Confessio amantis; and, finally, between scribes and their scriptural performances, in an overview of the calligraphic oeuvres of three late-medieval scribes, John Shirley, Ricardus Franciscus, and John Lacy. The distinctive power of the “hermeneutics of the books” I develop over the course of these analyses brings into view a dimension of late medieval English literature—and of the books that preserve it—that may not be accurately understood as either material or textual: an illusory, imaginary space that resides most properly in the eye of a beholder with the bibliographic sensibility that characterized late medieval English manuscript culture.