This volume follows recent work on the concept of authority in ancient Greek and Roman philosophy, and it sheds light on the Platonic tradition by examining different conceptions of authority from Plato’s immediate successors to late Neoplatonists. In their Introduction, the editors stress that by defining the specific grounds and function of a thinker’s conception of authority, a discontinuous but more honest history of the long tradition of Platonism can be told. Such prefatory comments give the impression that the volume’s contributions will not be well integrated. But, except for a lack of cross-references between them, the chapters are on the whole complementary and benefit from being published together. This is particularly true of those chapters that deal with conceptual issues concerning the grounds or nature of authority (Petrucci, Boys-Stones, Tornau, and, to a lesser extent, Aerts). Those chapters that attend more to the deployment of authority for polemical or legitimizing purposes (Sedley’s two chapters, Ioppolo, Centrone, Michalewski, Chiaradonna, and Sheppard) ought to be read in light of the former set.