Given the limited textual evidence, Protagoras is one of the most riddling characters to read within a coherent frame in the history of western thought. In his short three-chaptered survey on Protagoras, S. explores the sophist's historical background and theoretical ideas. Simply put, S. suggests that: (1) by his education under Democritus, Protagoras became a sceptic concerning the true entities beyond human interests and ‘a professional educator with special focus on his introduction of the practice of charging for instruction’ (p. ix); (2) under the influence of Protagoras’ political thought, Pericles set out to effect democratic reform, but ended up pursuing imperial ambitions for Athens; and (3) Protagoras had a set of ethical systems, one public for ‘noble defense of equal rights for all citizens’ (p. x), i.e. ‘defense of democracy’ (p. ix), and the other private, or ‘secret’, for fostering a powerful statesman who stands beyond the law to acquire ‘the best means for maximizing one's self-interest’ (p. x), namely a type of tyrannical elitism. These three claims are set out in each chapter respectively.

In the first chapter, S. argues that Protagoras was guided by Democritus’ epistemological scepticism and ethical enlightenment into a relativist position in which he ‘celebrates humans as the measure of all reality and dismisses any truth claims beyond this vantage point’ (pp. 6–7) and affirms that ‘each individual must judge the truth of things for himself’ (p. 13) (Man-Measure: DK80 B1), while taking an agnostic viewpoint concerning the gods (On the Gods: DK80 B4). Since he himself began his career as a porter responsible for transporting heavy loads (cf. DL 9.53 and DK80 A3, A3a), Protagoras commenced his teaching profession with the humble aim of taking care of the poor, but eventually turned to pursuing the favour of the wealthy. The experience of teaching both classes made Protagoras capable both of education for the public through eloquent speeches and of private lessons in which he secretly delivered his maxims to the wealthy in return for money.

The second chapter shows that the conversion of Pericles’ political intention is supported by Protagoras’ political thought. S. first discusses that Pericles’ initial political desire for democratic reform was due to Protagoras who was ‘the first democratic political theorist’ (p. 21). Pericles ‘affirms Protagoras’ radical conception that the consent of the community is the only arbiter of right and wrong … defending the superiority of democracy over other regimes since the ruling majority only needs to impose its will on a small segment of the population’ (p. 41). However, as Plutarch suspected, Pericles seems to have in the end desired to rule Athens, and other cities in the Delian League as well, as a tyrant, acting just like the Thrasymachean stronger whose advantage is defined to be justice (cf. Rep. 339a). How could someone who was taught by the first democratic theorist turn out to desire ruling like a tyrant? With the assertion that ‘Protagoras taught Pericles how to realize these aspirations’, i.e. to rule as a tyrant, ‘as the wise orator able to impose his will over the masses’ (p. 43), S. opens the following chapter to seek Protagoras’ theoretical foundation of Pericles’ conversion of political intention from democracy to political elitism.

In the last chapter, S. ventures to reveal the contents of Protagoras’ two aspects of political teachings. Protagoras wears a mask of democratic claim for the universal morality that men are born with the capacities of what is right and shameful, dikê and aidôs (in S.’s words: ‘political wisdom’ or ‘knowledge’), to be politically virtuous and wise. However, ‘this potential is only realized through “application and learning”’ (epimeleia and mathêsis) (p. 62), and men have ‘no innate disposition to act in a specific way’ (p. 71). On the basis of the images of the gods in Greek literature, that they remain beyond the law with the right to order others to serve for their own interests, S. argues that, while the majority struggle to survive with the weapons of rationality, ‘Protagoras teaches the elite how they can use rhetoric to stand outside of the law like one of the Olympian deities’ (p. 75) and employ ‘noble lies to manipulate the masses’ (p. 56) for the elite's own ends. S. adds that, as it was common for ancient Greek thinkers to secretly run private lessons restricted to their genuine followers, so too did Protagoras for his secret teaching of immoral elitism.

Some doubts about S.’s interpretation seem unavoidable. First, the evidence for the connections between the characters is insufficient. The date of Protagoras is not consistent with his having been taught by Democritus, and the story of their association comes only in much later writers from the second to the tenth centuries a.d., such as Apuleius (DK80 A4), Gellius, Philostratus (DK80 A2), Diogenes Laertius (DK80 A1), Hesychius (DK80 A3) and Suda (DK80 A3a). In addition, despite the well-known relationship between Protagoras and Pericles (cf. DK80 A10, A11 and B9, etc.), there is no evidence that Protagoras is indeed responsible for Pericles’ political conversion. S. here relies on evidence that seems somewhat irrelevant to Protagoras, such as Plutarch's Pericles, Thucydides’ Peloponnesian War and even the Thrasymachus of Plato's Republic.

Second, S. seems to take it for granted that any representation of Protagoras is reliable evidence for the sophist's views. We must be careful, however, to differentiate between evidence ascribed to Protagoras as fragments of his own works and other representations of the sophist in Protagorean texts. The former may derive from Protagoras, but the latter may be creations by other authors for their own purposes; the Man-Measure and On the Gods would be of Protagoras’ fragments, while the Great Speech is probably one of the Protagorean texts. An interpretation based on a mixture between Protagoras’ fragments and Protagorean texts without further justification is on dangerous and fragile ground.

Third, the gods represented in the Great Speech could be merely Protagorean rhetoric to emphasise that dikê and aidôs given by Zeus are the significant signs of human nature to be political, just as the technical wisdom and fire distributed by Prometheus are the indications of human nature to be rational, rather than pointing us towards an implication of tyrannical elitism. Zeus thus ordains that all men must possess these capacities, and anyone who lacks them should be killed (cf. Prot. 322d), that is, he should not be counted as a being with human nature. With the natural capacities to be virtuous all men can be political. Yet, the more opportunity one has for epimeleia and mathêsis about political affairs, through either direct experiences or indirect experiences, the more opportunity one has for deliberation (euboulia) to deal with them virtuously, both in action and speech, in any sort of human communities (cf. Prot. 318e–19a). With a hope for the youth to be virtuous by education in political wisdom (cf. Prot. 328c–d), the Protagoras in Plato maintains empiricism of demotic pedagogy for a better life; and with his nearly 40 years of experience of professional sophistry around the Greek cities (cf. Men. 91d–e), he sees himself as the most experienced to teach the deliberation to anyone who wishes it. If this understanding of the Great Speech is correct, the Protagorean democracy remains secure for all, without concealing a secret claim for immoral elitism that prevents the majority from having an effectively virtuous and powerful life in a human community.

S.’s volume is interesting and contains much information on the sophistic theories and their influences in political realms; his attempt to explain Pericles’ political conversion in light of Protagoras’ two ethical teachings is particularly intriguing. It would, however, have benefited from more careful arguing on the grounds of convincing use of the evidence for Protagoras.