Andrew J. Mason’s book systematically develops the compelling idea that the early and middle Plato conflates flow and flux when opposing the changing world of sensible things to what truly is: while flow can be characterized as the continuous, directed motion and change of something, flux indicates a chaotic, intrinsic alteration that transform some fleetingly existent thing into something else. In the late Plato Mason finds traces of such a distinction that also show that only flux, but not flow, is incompatible with being. Mason’s investigation is very rich in its wide scope: not only does he look at a broad range of Platonic dialogues, and at the linguistic, cosmological, as well as ethical dimension of the distinction between flow and flux, he also persuasively situates Plato’s usage of the words "¿¿¿" and "¿¿¿” in the wider context of Pre-Platonic philosophers and poets.- Barbara Settler, St. Andrews, UK