Book Eight centers on the battle of Salamis. If Thermopylae, the inspiring defeat, is the better-known battle, Salamis was an actual victory, won through superior Greek tactics, in a venue where Greeks feel particularly at home: the sea. The Homeric-style ship catalogues in 8.1 and 8.43 are a nice touch, and the divine interventions are also reminiscent of Homer, such as a storm destroying the Persian fleet in 8.12 (“done by a god, that the Persian armament might be made equal to that of the Greeks and not much greater”), or the miracles at Delphi (8.37), in which arms moved themselves, and lightning struck and chunks of cliff fell on the enemy. Themistocles himself in 8.109 attributes the victories to “gods and heroes” who desired that one man should not rule both Europe and Asia.
The Olympic games are characteristically Greek and used by Herodotus to burnish the Greeks’ reputation. First, there is the passage in 8.26 when the deserters from Arcadia explain to the Persians that the Greeks compete in the games for an olive crown, to which Tigranes exclaims, “What sort of men have you led us to fight against, who contend, not for money, but purely for the sake of excelling?”, a pro-Hellenic sentiment if there ever was one. In 8.59, discussions in the Greek council of war refer to the games: Admiantus says that “those who get off the mark too soon are whipped,” to which Themistocles replies, “but those who get left behind never get crowned.” (One can imagine any number of sports metaphors expressing similar ideas today, e.g. Wayne Gretzky’s observation that “you miss 100% of the shots you don’t take”). Finally, Eurybates and Themistocles received actual victors wreaths from the Spartans. Thus does the Greek athletic spirit inspire a successful fighting spirit, and illustrates the superiority of the Greeks to the barbarians. (8.86: “Proper discipline and ordered ranks” vs. “no order and no… sense of purpose.”)
Herodotus does deal with some Greek cleverness that does not necessarily reflect well on their side. Artemisia may have escaped from Salamis through subterfuge (8.87), but Themistocles himself convinced the Greeks not to pursue the Persians, intending “that this act should be as a reserve to his credit with the Persians, that he might have a refuge if, one day, trouble overtook him” (8.109), which indeed came to pass.
As for his own sources, Herodotus indicates that there is slight disagreement between the Athenians and the Aeginetans about the progress of the battle of Salamis (8.84). He indicates that the Delphians told him things directly in 8.39. But he cannot bring himself, in 8.8, to name the source of the story of Scyllias of Scione, the best diver in Greece, who allegedly swam ten miles underwater: this exploit is treated with the passive voice (“it is told” and “it is said”), and Herodotus is deeply skeptical of “other stories” about him. No miracles here.