The most difficult question posed by the Cold War is why it did not end in hot war. Odd Arne Westad, a professor of history at Harvard, argues persuasively that it very nearly did: ‘On a couple of occasions, we were much closer to nuclear devastation than anyone but a few people realized. Nuclear war could have broken out by accident, or as a result of intelligence failures.’ In 1962 Fidel Castro seems to have believed that the Cuban Missile Crisis would end in thermonuclear warfare. In what he probably intended as a farewell letter to Nikita Khrushchev, he urged him to take the ‘harsh and terrible’ decision to launch a nuclear first strike against the United States if it invaded Cuba.

When peace between the two nuclear superpowers hung by a thread during the missile crisis, it is difficult to resist the conclusion (which Westad does not quite arrive at) that the personalities of the US and Soviet leaders made a major, perhaps crucial, difference. CIA files reveal that, unlike President