Moses Maimonides was a Renaissance man before there was a Renaissance: a great physician who served a sultan, a dazzling Torah scholar, a community leader, a daring philosopher whose greatest work——The Guide for the Perplexed——attempted to reconcile scientific knowledge with faith in God. He was a Jew living in a Muslim world, a rationalist living in a time of superstition. Eight hundred years after his death, his notions about God, faith, the afterlife, and the Messiah still stir debate; his life as a physician still inspires; and the enigmas of his character still fascinate.