The title of Charles Taliaferro's book is derived from poems and stories in which a person in peril or on a quest must follow a cord or string in order to find the way to happiness, safety, or home. In one of the most famous of such tales, the ancient Greek hero Theseus follows the string given him by Ariadne to mark his way in and out of the Minotaur's labyrinth. William Blake's poem "Jerusalem" uses the metaphor of a golden string, which, if...