The diplomat and historian George F. Kennan (1904–2005) ranks as one of the most important figures in American foreign policy. Drawing on many previously untapped sources, Frank Costigliola's biography offers a new picture of a man of extraordinary ability and ambition whose idea of containing the Soviet Union helped ignite the Cold War but who spent the next half century trying to extinguish it. Always prescient, Kennan in the 1990s warned that the eastward expansion of NATO would spur a new cold war with Russia. Even as Kennan championed rational realism in foreign policy, his personal and professional lives were marked by turmoil. And though he was widely respected and honored by presidents and the public, he judged his career a failure because he had been dropped as a pilot of US foreign policy. Kennan was a trenchant critic of both communism and capitalism, and a pioneering environmentalist. Living between Russia and the US, he witnessed firsthand Stalin's tightening grip on the Soviet Union, the collapse of Europe during WWII, and the nuclear arms race of the Cold War. An absorbing portrait of an eloquent, insightful, and sometimes blinkered iconoclast whose ideas are still powerfully relevant, Kennan invites us to imagine a world that Kennan fought for but was unable to bring about—one not of confrontations and crises but of dialogue and diplomacy.