The Peloponnesian War ended an era of sociopolitical progress. Sparta’s defeat of Athens discredited democratic government as well as a flourishing art and culture: the war’s barbarism prompted the relapse of Greek civilization. Kagan extends beyond retelling Thucydides’s master work by incorporating the findings of modern scholars, or synthesizing the greater, more prominent controversies. Left to the reader’s judgement are the related questions of how Pericles strategy of outlasting Sparta through civic sacrifice could have been improved, and how two ideologically opposed powers on a collision course can coexist?