At the beginning of August 1974, as Richard Nixon’s presidency was dribbling painfully away, he called his successor Gerald Ford in to see him. It was a tense, awkward meeting, but Nixon did offer one useful bit of advice. At all costs, he recommended, Ford should keep Henry Kissinger on as Secretary of State. ‘Henry is a genius,’ he said thoughtfully of his great collaborator, ‘but you don’t have to accept everything he recommends. He can be invaluable, and he’ll be very loyal, but you can’t let him have a totally free hand.’ Later, Nixon was even more forthright: ‘Ford has just got to realise there are times when Henry has to be kicked in the nuts,’ he told an aide. ‘Because sometimes Henry starts to think he’s president. But at other times you have to pet Henry and treat him as a child.’

Although Nixon had some decidedly eccentric opinions (his belief, for example, that the rise of dope-smoking was being orchestrated by a Jewish conspiracy), his characterisation of Henry Kissinger was not one of them. At once brooding and brilliant, self-mocking and self-promoting, impulsive and calculating, Kissinger remains one of