This dissertation aims to find the life in hagiography. That is, this project breaks with traditional readings of medieval saints' lives in order to examine what constitutes -life[DOUBLE VERTICAL LINE] in these narratives. While medieval hagiography has been mined by contemporary scholars for political, social, and ecclesiastic content, little attention has been paid to the genre's relationship to philosophical and organic categories of life. I argue that not only do these lives engage in philosophical wranglings about ontology but that their literary inclinations also attach hagiographic forms to a kind of presence that resists transcendence while still acknowledging a theological tradition. Although the vast corpus of medieval life-writing seems potentially universal in scope and content, this study organizes around the idea that medieval life narratives prove flexible enough to permit speculation about living energies and bounded enough by genre, convention, and doctrine to develop the idea of vitality carefully and intentionally. The first part of this project addresses the living being through a literary-historical lens that endeavors to trace the evolution of this concept as it is connected to a trajectory of holiness in post-Conquest England. The injunctions and caesurae of monastic living highlight the medieval sense of the instability both of the living being and of a working understanding of it. The lives of saints native to the British Isles whose legends feature encounters with animals reveal how animal lives can map spaces in the vita for other living beings. Studying next the means by which Geoffrey Chaucer and the Pearlpoet attend to the difficulties in locating and representing the space and dynamism of life, I explore how vital objects, landscapes, and minerals affirm the place of nonhuman life in the human life. Finally, a look at Piers Plowman illustrates that the later fourteenth-century life grows through its connections to the problems of knowledge, imagination, and spiritual histories to create a type of ecological entanglement. The medieval life, I conclude, is not merely concerned with exemplary living, but rather imagines the living being as constituted in a network, as patched together with materials, nonhuman beings, other human beings, ideas, and histories.