What is the force in art, C. Stephen Jaeger asks, that can enter our consciousness, inspire admiration or imitation, and carry a reader or viewer from the world as it is to a world more sublime? We have long recognized the power of individuals to lead or enchant by the force of personal charisma--and indeed, in his award-winning Envy of Angels, Jaeger himself brilliantly parsed the ability of charismatic teachers to shape the world of medieval...