The vita of the reformed prostitute Mary of Egypt was a popular narrative in the middle ages, but its appeal is enigmatic to a modern audience. This study explores the narrative power of the Old English Life of St. Mary of Egypt through an analysis of its hermeneutic structure: the narrative constantly foregrounds the importance of the reader in the hermeneutic circle, moving back and forth between the "known" of the reader's expectations, and the "unknown" of the text's silences. On another level, the vita also depicts the impulse to transcend the too-familiar limitations of the flesh, and ascend into the undiscovered realms of the spirit. In order to represent this deep loathing of the body, the narrative constructs a binary opposition between the masculine ascetic body and the feminine sexual body, both in turn characterized by opposing notions of somatic integrity. The foundation and transgression of boundaries - again a dialectic between known and unknown - extends to the topographical representations of the narrative and the ritualistic patterns traversing these boundaries. The text's complex rhetoric of boundaries and transgressions is a hermeneutic strategy used to explore the meaning of masculine bodily experience.