Augustine of Hippo (Thagaste, b. 354–Hippo, d. 430 ce) brings the very person of the thinker onto the philosophical scene for the first time in the history of philosophy, with his existential vicissitudes, his spiritual travails, and his incessant search for truth. Augustine is the ancient figure we know better than anyone else, thanks to the fact that he himself has narrated in the Confessions the external and internal events of his life, from his childhood spent in Roman Africa to his conversion to a radical and demanding form of Christian existence in 386. His conversion also marks the moment in which faith is consciously and programmatically assumed as the starting point of a rational itinerary that aims at understanding the most important truths about God and the human being. Augustine’s contribution to philosophical and theological thought is broad and manifold, from the theory of knowledge and language to the conception of evil and freedom, from the doctrine of creation and time to the analysis of the mind and its acts, from the most difficult questions concerning divine grace and the Trinity to the reading of human history as the interweaving of two mystical ‘cities’. Fundamental terms of the intellectual language of the West—such as ‘sign’, ‘free will’, ‘original sin’, ‘predestination’, ‘relation’—bear the indelible imprint of Augustine’s reflection. Especially sensitive to the influence of Plotinian and Porphyrian Neoplatonism, the gigantic work of this Father of the Church—an essential link between Antiquity and the Middle Ages—has in turn influenced Western Christianity like few others, and through it European culture, right up to modern and contemporary times. Although in Augustine’s thought one cannot clearly distinguish between philosophy and theology, in this article only his works and themes that have greater philosophical prominence today are considered. Therefore, purely theological topics such as the doctrine of divine grace are excluded. Only books published or republished after 1970 are cited, with a few rare exceptions. The remaining bibliography (earlier books, essays contained in collective volumes, and journal articles) can be found by consulting the section Bibliographies.