A new translation of Martin Heidegger's early work "Augustine and Neoplatonism ", originally published in 1921. This edition contains a new afterword by the Translator, a timeline of Heidegger's life and works, a philosophic index of core Heideggerian concepts and a guide for terminology across 19th and 20th century Existentialists. This translation is designed for readability and accessibility to Heidegger's enigmatic and dense philosophy. Complex and specific philosophic terms are translated as literally as possible and academic footnotes have been removed to ensure easy reading. In the summer semester of 1921, Heidegger lectured on "Augustinus and Neoplatonism. The original manuscript, consisting of 19 pages, contains a continuous text on the left and space for notes on the right. The complex nature of Heidegger's marginal notes, often interspersed with the main text, required careful transcription. The editors have ensured clarity by enclosing the notes in round brackets and placing them at the end of each paragraph. The edition also includes additional material relating to Heidegger's studies of religion and mysticism in 1918/19, which sheds light on the development of his early philosophical ideas. The thorough work of the editors, together with the collaboration of the contributors, contributes to a comprehensive understanding of Heidegger's lectures and their significance for his philosophical development. Heidegger critically examines Augustine's incorporation and transformation of Neoplatonic concepts, focusing in particular on notions of Being, temporality, and selfhood. This analysis is not a mere historical account, but a phenomenological exploration of how Augustine reconceptualizes these ideas within a Christian framework. He examines Augustine's concepts of 'being', 'temporality', and 'ontology' and shows how they are deeply influenced by Neoplatonic philosophy. Heidegger's approach, however, is not merely to trace philosophical influences, but to uncover the existential dimensions in Augustine's thought. Heidegger illuminates how Augustine navigates and redefines the Neoplatonic heritage in order to address fundamental questions of existence, truth, and the human condition within a Christian paradigm. Heidegger's exploration is thus both a critical analysis of Augustine's philosophical adaptation and a reflection on the existential and phenomenological implications of this synthesis. He notes that while both Judaism and Christianity contain inherently Platonic Ontological concepts, Augustine further synthesized Neoplatonism around the conceptualization Dasein to form a distinctly Latin flavor of Theanthropic Philosophy.