I've been reading Donald Kagan's one-volume The Peloponnesian War, and for the first time, I feel like I understand what went on back in Greece, oh, about 2400 years ago. Kagan devoted the better part of his academic life to a detailed, 4-volume study of the subject, which is the current standard in the arena. By reducing the war to one volume, he's able to keep it accessible to readers who don't care for the minutiae of hoplite organization. A map is never far away from whatever page you're on, and the text frequently refers you to the one you need just then. Wars combine political, military, and diplomatic maneuvering, and Kagan is able to keep track of the most important of these at any given time, without cluttering up the reader's attention.

One of the reasons that you read history, especially Big History, is to apply those lessons to today. One lesson is the inherent instability of a bipolar system. Athens and Sparta fought a war prior to the one in question, and concluded a treaty which both sides clearly intended to keep to. Still, when a marginal quarrel erupted, in which neither bloc had a horse to start out with, both sides were drawn into it. This happened from time to time during the Cold War, too, but it lends credence to the notion of nuclear deterrence as peace-keepers.

Also, Athens started out with a strategy of deterrence, but one based on so unorthodox a strategy that it failed to convince, and thus, to deter. There was a significant peace party in Sparta, led by the King, but they had lost the vote, and needed the hand to be strengthened by a strong Athenian showing. Instead, Athens failed to prosecute its advantages to the fullest. Many of those advantages were psychological rather than actual, so a prolonged war was liable eventually to expose their weaknesses and inspire their internal and external enemies.