John Allen’s book goes a long way toward explaining the central enigma surrounding Ratzinger: How did this erstwhile liberal end up as the chief architect of the third great wave of repression in Catholic theology in the twentieth century? Based on extensive interviews with the cardinal’s students and colleagues, archival research in his native Bavaria, and a thorough familiarity with his writings, Allen’s account shows how the roots of Ratzinger’s deep suspicion of “the world,” his preoccupation with human sinfulness, and his demand for rock-solid loyalty to the church go deep.