This book is, in the first place, a historical study. It seeks to discover and to understand a slice of the past: the particular slice being the thought of St Augustine of Hippo on a particular cluster of themes. Its object is not to cover ground already adequately covered. Even in English alone, there are several good expositions of Augustine's political thought. Accordingly, much that falls within the field generally recognised as ‘political theory’ is here not dealt with at all, or only touched on lightly. I have, for instance, allowed myself only the briefest of discussions of law, and not considered such cognate themes of Augustine's reflection as property, justice or war. On the forms of government and on the right way to exercise its functions even the little that Augustine has to say has fallen outside my scope. On the other hand, much of the book is concerned with subjects which would not normally be found in an exposition of Augustine's political thought. My purpose has been to consider the fundamentals of the way in which Augustine conceived the social dimension of human, especially Christian, existence. This is why much of the book is concerned with themes such as Augustine's vision of history and of God's work in human history. Such discussions have at times landed me in considering even more distant topics, such as, for instance, Augustine's views on prophetic inspiration, or on youth and age.