My subject today is perhaps the most famous and influential of the Platonic dialogues, the Republic. This immortal work, which may fairly be described as the founding charter of Western civilisation, deals with many questions of fundamental importance in the fields of philosophy, education, political science and economics. My concern, however, is the central theme of the dialogue; the inquiry into the nature and operation of justice. This quest is the subject of a mighty debate between Socrates and his associates. Reason is the golden thread which runs through this debate, as it does through the whole of Platonic teaching. What is justice? Is justice more profitable than injustice? How does justice in the individual differ from justice in the State? What are the respective rewards of justice and injustice? These are but some of the questions, all of them of timeless importance to mankind, that are so vigorously and profoundly explored by Socrates and his companions.