In the fourth and final volume of his magisterial history of the Peloponnesian War, Donald Kagan examines the period from the destruction of Athens' Sicilian expedition in September of 413 B.C. to the Athenian surrender to Sparta in the spring of 404 B.C. Through his study of this last decade of the war, Kagan evaluates the performance of the Athenian democracy as it faced its most serious challenge. At the same time, Kagan assesses Thucydides' interpretation of the reasons for Athens' defeat and the destruction of the Athenian Empire.