For nearly eight years, until his decision to resign on the last day of February 2013, Joseph Ratzinger was Pope Benedict XVI, the most visible exponent of Catholicism in the world—a universal pastor and renowned theologian, who presented his ideas and exhortations in homilies and speeches around the globe and deeply researched books about Jesus. Today he lives in a monastery on the Vatican grounds, a priest and a theologian, a leader “hidden from the world.”