 Augustine’s literary output surpasses the preserved work of almost all other ancient writers in quantity. In the Retractationes (“Revisions”, a critical survey of his writings in chronological order down to 428 CE) he suggests a threefold division of his work into books, letters and sermons (Retractationes 1, prologue 1); about 100 books, 300 letters, and 500 sermons have survived. Augustine’s literary career after his conversion began with philosophical dialogues. The first of these, written in Cassiciacum in 386/7, deal with traditional topics such as skepticism (Contra Academicos), happiness (De beata vita), evil (De ordine) and the immortality of the soul (Soliloquia, De immortalitate animae). Augustine continued to pursue these issues in dialogues on the immateriality of the soul (De quantitate animae, 388), language and learning (De magistro, 388–391), freedom of choice and human responsibility (De libero arbitrio, begun in 388 and completed perhaps as late as 395) and the numeric structure of reality (De musica, 388–390). The treatise De vera religione (389–391) is a kind of summa of Augustine’s early Christian philosophy. After the start of his ecclesiastical career he abandoned the dialogue form, perhaps because he realized its elitist and potentially misleading character (G. Clark 2009; Catapano 2013). Of the works from his priesthood and episcopate, many are controversial writings against the Manicheans (e.g., Contra Faustum Manichaeum, around 400), the Donatists (e.g., Contra litteras Petiliani, 401–405; De baptismo, 404) and the Pelagians (e.g., De spiritu et littera, 412; Contra Iulianum, 422; De gratia et libero arbitrio, 424–427; and his last and unfinished work Contra Iulianum opus imperfectum, which preserves a substantial portion of the otherwise lost treatise Ad Florum by his Pelagian adversary Julian of Aeclanum). Among the philosophically most interesting of these works are De utilitate credendi (391–392, a defense of faith/belief against Manichean rationalism), De natura boni (399, a concise anti-Manichean argument for the doctrine that evil is a privation of goodness rather than an independent substance), De natura et gratia (413–417, a reply to Pelagius’ treatise De natura) and De correptione et gratia (426/427, refuting a Christian version of the Stoic ‘Lazy Argument’ that had been put forward against Augustine’s doctrine of grace). Augustine is however most famous for the five long treatises with a wider scope he composed between 396 and 426. The Confessiones (ca. 396–400), probably his most original work, is “philosophy in autobiography” (Mann 2014) rather than an autobiography in a modern sense. It shows how an individual life—Augustine’s own—is made sense of by God’s providence and grace as well as by his creation and economy of salvation. De doctrina christiana (begun in 396/7 but completed only in 426/7) is a handbook of biblical hermeneutics and Christian rhetoric; it delineates the semiotic dichotomy of “things” (res) and—especially linguistic—“signs” (signa) and critically assesses the importance of the classical disciplines for the biblical exegete. De trinitate (begun in 399 and completed in 419 or perhaps as late as 426) has impressed modern philosophical readers by its probing analyses of the human mind as an “image” of the Divine Trinity. De Genesi ad litteram (401/2–416) is an attempt at winning a philosophically justifiable cosmology from the opening chapters of Genesis. Here as in most of Augustine’s works philosophy is inseparable from biblical exegesis. The monumental apologetic treatise De civitate dei (begun in 412, two years after the sack of Rome, and completed in 426) argues that happiness can be found neither in the Roman nor the philosophical tradition but only through membership in the city of God whose founder is Christ. Among many other things, it has interesting reflections on the secular state and on the Christian’s life in a secular society. The sermons document Augustine’s ability to adapt complex ideas to a large and not overly learned audience. Two long series on the Psalms (Enarrationes in Psalmos, ca. 392–422) and the Gospel of John (In Iohannis evangelium tractatus, ca. 406–420) stand out; a series of sermons on the First Letter of John (In epistulam Iohannis ad Parthos tractatus decem, 407) is Augustine’s most sustained discussion of Christian love. The letters are not personal or intimate documents but public writings that are part of Augustine’s teaching and of his ecclesiastical politics. Some of them reach the length of full treatises and offer excellent philosophical discussions (Letter 155 on virtue; Letter 120 on faith and reason; Letter 147 on the “seeing” of God).