The books in this set, originally published between 1939 and 1991: Focus on the concept of virtue, and in particular on the virtue of wisdom or knowledge, Study the pilgrimage of the Ancient World in its search for moral truth. Discuss the political implication of the spread of science in antiquity. Examine the nature of Pre-Socratic thought and the three pluralist responses of Empedocles, Anaxagoras and the early Atomists.