When H. L. Mencken talked, everyone listened -- like it or not. In the Roaring Twenties, he was the one critic who mattered, the champion of a generation of plain-speaking writers who redefined the American novel, and the ax-swinging scourge of the know-nothing, go-getting middle-class philistines whom he dubbed the "booboisie." Some loved him, others loathed him, but everybody read him. Now Terry Teachout takes on the man Edmund Wilson called "our greatest practicing literary journalist," brilliantly capturing all of Mencken's energy and erudition, passion and paradoxes, in a masterful biography of this iconoclastic figure and the world he shaped.