A mathematical genius in eleventh century Persia is persecuted for his admiration of Greek philosophers and his rebellious poems, the two worlds of Christianity and Islam slowly move towards their most violent embrace in the Crusade of 1096, and a companion of emperors and queens is abandoned to the mob once the appeasement of enraged mullahs becomes more important in a dynastic war than the life-long devotion of a friend, doctor, musician and astronomer. Omar Khayyam has been the world’s favourite poet since 1859. His slim book of poems, the Rubaiyat, as translated by Edward FitzGerald, has become a masterpiece of English literature in its own right and rendered into almost all the world’s other languages. The consequences have been spectacular. Astronomers have named a crater on the moon after him and some mathematicians regard him as one of the top ten intellects in history. Yet this biography is the first detailed study of his life to merit the description. Such was the excitement during its preparation that the Chinese national radio sent its reporter in London to interview its author and the BBC’s Today Programme devoted a chunk of its time to mark its publication.