In this modern account of the genesis of a great medieval myth, celebrated science fiction author Robert Silverberg's explores the mysterious origins of Prester John, the astonishing Christian potentate of the East.

Prester John was a legendary figure who cast a powerful spell over Latin Christendom for almost five centuries. Rumors of the warrior-king-prelate's fabulous realms first reached Europe in the eleventh century and quickly assumed an exalted status alongside such fabled wonders as El Dorado, The Fountain of Youth, and the Holy Grail.

The defeat of a Moslem Turkish tribe by a Buddhist Chinese warlord seems to have been the unlikely historical nugget around which the Prester John myth grew, but contributions to this strange saga have also been traced all around the globe to the Apostle Thomas' apocryphal preaching in India, to the actual existence of small colonies of Nestorian schismatics in central Asia, and even to Genghis Khan.