As a young priest, Robert Prevost was sent in 1981 to Rome to study church law at the Pontifical University of Saint Thomas (known as the Angelicum). There he earned a licentiate and composed a doctoral thesis, which made final in 1987. This is that thesis, the first book-length work composed by the man now known as Pope Leo XIV. Specifically, his study - drawing from sources in English, Italian, and Spanish and from medieval history and theology as well as canon law - focused on the role of the prior as the local superior in the Order of St. Augustine. In doing so, he describes a traditional notion of obedience in religious life - one based on love of the truth and growth in one's inner freedom to pursue holiness. At the center of his reflection are key ideas regarding the common good of the Church; the Eucharistic liturgy at the center of the life of the community; the role of hierarchy and consultation; and mutual respect for the diverse contributions of each person. Present in this text, moreover, is a far-reaching conception of the priesthood characterized by the triple munera: the priestly work of teaching, sanctification, and governance. Central to the whole volume is an Augustinian conception of the spiritual life that focuses on the inward work of grace, the primacy of the love of God, and inward conformity to Christ. The book's preface - composed by eminent theologian and present-day rector of the Angelicum, Fr. Thomas Joseph White, OP - helps frame the work for the wider public interested in it as a privileged window into the mind and heart of Prevost as a young priest, showing how its subject matter has implications for how one thinks about the life of the Catholic Church. There are clearly in this early work central themes regarding the life of Church, the apostolic tradition, and ecclesial authority in the service of the common good, that may well indicate directions and themes in the subsequent life and teaching of the author. Canonists will be drawn to Prevost's analysis of the Constitutions of the Augustinians in light of the then-newly promulgated Code of Canon Law. Historians and theologians alike may enjoy considering parallelisms that occur between this Augustinian vision of the prior and the subsequent unfolding of an Augustinian pontificate. Hopefully the publication of this work will lead to constructive debate about and comprehension of the relation of between the two.