Barely two weeks into 1979. Iran's Shahanshah, King of Kings, Light of the Aryans, Mohammed Reza Pahlavi, fled his country--which was then in the final throes of a revolution led by an austere anti-Western theocrat known as Ayatollah Ruhollah Khomeini. Following an 18-month hegira that took him through a half dozen nations, the Shah died of cancer. Shawcross (Sideshow, The Quality of Mercy) here offers an engrossing narrative that combines an affecting journal of the deposed monarch's last days with informed perspectives on the events preceding his banishment. By the author's account, the Shah never really understood the reasons for the collapse of his government, which had been both corrupted and sustained by the availability of immense oil revenues. Nor did he grasp that the fidelity of sometime allies was to Iran and its strategic values rather than to his person. At any rate, when the Shah was driven into exile, precious few states were willing to grant him hospitality, let alone asylum. Only Anwar Sadat proved steadfast as the Shah and his dwindling entourage shuttled through Egypt, Morocco, the Bahamas, Mexico, the US, and Panama, then back to a rendezvous with death in Cairo. As a practical matter, countries reluctant to provide the itinerant Shah a haven had legitimate cause for concern. Soon after Washington allowed him entry for medical treatment, Islamic militants occupied the American embassy in Teheran and held the diplomatic personnel trapped there as hostages for well over a year. At the end, the forlorn Shah paid a high personal price for his regime's autocratic misrule and pretensions. When hounded from the Peacock Throne, he was already suffering with the cancer that would ultimately take his life. As Shawcross makes abundantly clear, though, the Shah's treatment at the hands of eminent, ego-tripping physicians of variant nationalities was the medical equivalent of opera bouffe. While he endured his ordeal with stoicism, even grace, the Shah's plight was longer on pathos than tragedy. Shawcross provides more clinical detail than most readers may care to know on precisely what ailed the Shah. This quibble apart, he offers a brilliantly allusive portrait of an overthrown sovereign adrift in a world of failed loyalties.