On 31 December 1977, at a New Year’s Eve banquet at Niavaran Palace in Tehran, the president of the United States, Jimmy Carter, raised a glass in honour of his host, Mohammad Reza Pahlavi, shah of Iran. ‘Iran, because of the great leadership of the shah,’ he declared, ‘is an island of stability in one of the more troubled areas of the world.’ Just weeks later, protests began that would grow in size and ferocity until, on 16 January 1979, just over one year after Carter’s speech, Mohammad Reza Pahlavi left Iran to spend the brief remainder of his life in exile. The United States had lost one of its closest allies and would soon gain one of its greatest adversaries. Iran became a theocratic state and political Islam emerged as a powerful ideology in the Middle East and beyond.

The question of how such a powerful state, with enormous oil wealth, an all-­pervading internal security apparatus, a vast and modern military and close relations with the West, could fall to a revolution has mystified generations of historians. In retrospect, one can point to myriad factors that accelerated the unrest through 1978. What is surprising is that hardly any scholars, diplomats or journalists had predicted the downfall of the shah. The revolution thus prompted foreign governments to reflect on what went wrong and why they were caught so off-guard. The British Foreign and Commonwealth Office and the CIA’s National Foreign Assessment Center, for example, immediately commissioned reports to examine their failures to anticipate the course of events. The failure of the United States to recognise either that a revolution was taking place or that Ayatollah Khomeini posed a danger to American interests constitutes a major thread in King of Kings, Scott Anderson’s impressive new study of the revolution.

Countless books have been written on the Iranian Revolution, yet historians return to the subject again and again because it defies simple explanation. As Anderson observes in his introduction, ‘the closer one examines it, the more mysterious and implausible it all seems’. He provides a captivating account of the final