Protagoras of Abdera was the most renowned of the Sophists; he was also the one who, by being the first to charge tuition fees for his courses, established Sophistry as a profession. He, more than anyone else, was responsible for the two key themes of Sophistry: the relativity of judgment and the teaching of the rhetorical arts. His intellectual reputation was therefore immediate and enduring. In Plato's Protagoras (circa 399 B.C.-387 B.C.) he was treated with great deference, and by the Hellenistic period he was regarded as sufficiently significant to have a statue of himself included among those of such respected figures as Plato and Aristotle in the Serapeum at Memphis, Egypt. Little of Protagoras's work has survived; what has survived exists only in fragments, few of which can be reliably assigned to Protagoras. Nevertheless, and despite the extensive controversy over the correct interpretation of his...