Ugo Zilioli is Leverhulme Researcher at the Faculty of Theology and Religion at the University of Oxford and Associate Member of Lady Margaret Hall, UK. He is author of Protagoras and the Challenge of Relativism: Plato's Subtlest Enemy (2007; 2nd edition 2016), The Cyrenaics (2014) and editor of From the Socratics to the Socratic Schools: Classical Ethics, Metaphysics and Epistemology (2015).