Grand strategy is the blueprint from which policy follows. It envisions a country's mission, defines its interests, and sets its priorities. Part of grand strategy's grandeur lies in its durability: A single grand strategy can shape decades, even centuries, of policy. Who, then, have been the great grand strategists among American statesmen? According to a slim forthcoming volume by John Lewis Gaddis, the Yale historian whom many describe as the dean of Cold War studies and one of the nation's most eminent diplomatic historians, they are John Quincy Adams, Franklin Delano Roosevelt, and George W. Bush. Gaddis knows the latter...