THUCYDIDES, XENOPHON, KAGAN AND HANSON. All have recounted and analyzed the Peloponnesian War...and the latter two have been frequent guests on our radio program. (The audio of our conversation with Donald Kagan is available here.) In this essay from the current New Yorker, Daniel Mendelsohn examines their contrasting views and the continued relevance of the great conflicy between Athens and Sparta.