In the late fourth and early fifth centuries of our era, Hypatia of Alexandria was the world s greatest living mathematician and astronomer. A strikingly beautiful woman and a devoted celibate, she lived in a city as turbulent and troubled as Baghdad or Beirut is today. She achieved fame not only in her special field, but also as a philosopher, religious thinker, and teacher who attracted a large popular following. Her life ended tragically in violence at the hands of a rampaging mob of Christian fanatics, who killed her for her "pagan" beliefs, some say at the instigation of St. Cyril of...