This illuminating and erudite book explores the meaning of grand strategy by recounting some of history’s most fateful decisions, many of which were also its most ill conceived. Often these involved attempts at conquest: the Persian king Xerxes’ invasion of Greece in 480 BC, Philip II of Spain’s abortive invasion of England in 1588, and Napoleon’s assault on Russia in 1812. Gaddis defines “grand strategy” as aligning “potentially unlimited aspirations with necessarily limited capabilities” and highlights the persistent error of focusing on the former while ignoring the latter. He frequently cites the philosopher Isaiah Berlin’s distinction, borrowed from the ancient Greek poet Archilochus, between the fox, who knows many things, and the hedgehog, who knows one big thing. The best strategists, Gaddis suggests, combine both attributes: they focus on overarching goals but respond pragmatically to circumstances. To make his point, he draws on a range of thinkers, including Thucydides, Machiavelli, Clausewitz, and Tolstoy. One surprise is that the period about which Gaddis has written most extensively—the Cold War and the nuclear age—is absent. Gaddis says he feels he has written enough on the subject, but this reader could have coped with a little more from the master of the field.