Julian Havil is the author of "Gamma: Exploring Euler's Constant", "Nonplussed!: Mathematical Proof of Implausible Ideas", "Impossible?: Surprising Solutions to Counterintuitive Conundrums", and "John Napier: Life, Logarithms, and Legacy" (all Princeton). He is a retired former master at Winchester College, England, where he taught mathematics for more than three decades.Julian Havil is the author of "Gamma: Exploring Euler's Constant", "Nonplussed!: Mathematical Proof of Implausible Ideas", "Impossible?: Surprising Solutions to Counterintuitive Conundrums", and "The Irrationals: A Story of the Numbers You Can't Count On" (all Princeton). He is a retired former master at Winchester College,… England, where he taught mathematics for more than three decades.Timothy Matovina is professor of theology and executive director of the Institute for Latino Studies at the University of Notre Dame. His books include "Guadalupe and Her Faithful: Latino Catholics in San Antonio, from Colonial Origins to the Present" and "Horizons of the Sacred: Mexican Traditions in U.S. Catholicism".