Augustine's first commentary on Genesis 1-3 has largely been approached as evidence of an overly philosophized Christianity rather than as an exhortation to openness to the mystery of Jesus Christ. I trace this bias to the co-opting of Augustinian early biblical exegesis: first by Robert J. O'Connell who defined it as the severing of biblical words (uerba) from the reality they express (res) and the supplanting of that res with a Plotinian res, and later by Roland J. Teske who carried forward O'Connell's definition and further entrenched it. In this dissertation, I propose and employ a new approach to the study of De Genesi contra Manichaeos (DGcM) that prioritizes both Augustine's main concern as expressed in DGcM and how he proceeds to address it in DGcM, Book 1. Contrary to the dominant readings of DGcM, I work to show that in addressing his main concern Augustine approaches Genesis 1-2:3 as a union of human words (uerba) and their immediate referents (the created realities (res) they signify) with a divine reality (res), a union that he claims yields an unfamiliar reality, a hidden truth, or 'mystery' in contradistinction to Manichaean falsehood or 'myth.' I argue this point through a close and careful study of the exegesis he provides for each verse. I first show that in interpreting each verse, Augustine presents the union between the letter, its immediate referent, and divine reality as one whose meaning and veracity are only discernible through an appeal to authorities or 'manifest realities.' I then show that in his interpretation of each verse, the 'manifest realities' Augustine turns to when examining this union include Genesis 1-2:3, the whole of Scripture, reality as experienced in creation and in being human, and reality as revealed most perfectly and fully in Jesus Christ's humanity, that is, His external teaching given in and through His words and deeds.