The year is 1140. Inside an imposing cathedral in France's Champagne region, two of the most recognized men in the world are about to face each other in a contest of wills and a test of faith. On one side is Bernard of Clairvaux, a counselor and selector of popes who will be called "Saint" even before his death. The other is Peter Abelard, widely agreed to be the era's most brilliant thinker, a medieval "rock star" among students in the universities...