Among the founders of western thought, Plato (c. 428–348 BCE) came from Athens, where he established the original Academy. His most celebrated student was Aristotle (348–22 BCE). So central were intellectual exchange and questioning for Plato that he wrote his works as dialogues, one voice being that of his own true-life tutor Socrates (c. 470–399 BCE). Harold Tarrant (Introduction and Abridgement) studied at Cambridge and Durham Universities, and worked at the University of Sydney from 1973 to 1993, when he took up the Chair of Classics at the University of Newcastle, Australia. Though now retired, he retains his Newcastle affiliation as Emeritus Professor. His principle focus is ancient Platonism, from Plato to Olympiodorus. He has authored or co-authored ten books in that field, and edited or co-edited others. Professor Marika Taylor (Series Foreword) is a Professor of Theoretical Physics and Head of School within Mathematical Sciences at the University of Southampton. Her research interests include all aspects of string theory, gravitational physics and quantum field theory. In recent years much of her work has been focused on holographic dualities and their implications. Marika's research has featured in such publications as Physical Review, Journal of High Energy Physics and General Relativity and Gravitation among others.