"Beginning his analysis with the Athenians' first formal contact with the Persians in 507 B.C., [Peter] Krentz weaves together ancient evidence with travelers' descriptions, archaeological discoveries, geological surveys, and the experiences of modern reenactors and soldiers to tell his story. Krentz argues that before Marathon the Athenian army fought in a much less organized way than the standard view of the hoplite phalanx suggests: as an irregularly...