The first biography of Luther in 50 years was, the author explains, prompted by the replacement of orthodox belief by a "bewildering variety" of cults. Luther, enraged by superstitions, was "bent on a ... quest" to restore faith. With impressive verve, Wilson explores the life of a troubled monk who viewed theological obscurity as "the most appalling cop out". When Luther attacked the sale of indulgences by Johann Tezel, a cross between PT Barnum and Churchill, he was in effect attacking the Pope. Though Luther may never have hammered his 95 Theses on the door of Wittenberg cathedral, still "they changed the world".