My dissertation demonstrates the importance of an examination of the literary works included as part of the curriculum in fourteenth- and fifteenth-century English grammar schools both for understanding the instruction of generations of schoolchildren and for reading the Middle English literature created and read by those trained in these schools. As Chapter 1 explains, thirty-four extant manuscripts used in an educational context in late medieval England, listed with their contents in the Appendix, suggest the identification of seven literary works that appear to have been taught most often: Disticha Catonis, Stans puer ad mensam, Cartula, Peniteas cito, Facetus, Liber Parabolarum, and Ecloga Theoduli. Considering these schoolbooks both individually and as a group reveals their usefulness for teachers and the instruction that they share: an emphasis on epistolary conventions, an awareness of the malleability of selves and social hierarchies, and the prioritization of ordinary human experience. As this project shows, the influence of the lessons of the grammar classroom pervades the production of vernacular literature and the reading practices of contemporary audiences. In Chapter 2, a reading of Chaucer’s Troilus and Criseyde informed with a knowledge of the formal features of letter writing, particularly the attention to audience stressed in the grammar schoolbooks, reveals Criseyde’s control of both the story’s ending and the responses of readers through her final letter to Troilus. Chapter 3 offers a reexamination of The Book of Margery Kempe that argues against Kempe’s presumed illiteracy and demonstrates how she utilizes classroom teachings on self presentation in both her lived experience and the writing of her Book to manipulate her reception by her contemporaries and readers of the text. The final chapter turns to the works of John Lydgate to show how he incorporated the schoolroom’s emphasis on the diversity of ordinary human experience into his influential Fall of Princes, thereby spreading grammar school lessons to new audiences. Appreciating the teachings of the literary schoolbooks thus enables not only a better understanding of the grammar curriculum that shaped schoolchildren for two centuries but also a recognition of schoolbooks’ profound effect on authors and audiences in late medieval England. / text