It must have been the heady atmosphere of those World War II days that made Edmund Wilson mount a frontal assault at one of the mainstays of Western civilization. "Who cares who killed Roger Ackroyd," he thundered in the title of his essay denigrating detective fiction. But having discharged this salvo the eminent critic must have been seized by some inner doubts. Obviously hundreds of thousands have cared, the vast legion of readers who for 300 pages have struggled with the plethora of clues, only to be left dazzled and emotionally drained by the astounding conclusion of Agatha Christie's masterpiece. Wilson thus beat a retreat to a higher, supposedly safer, ground: "Friends," he wrote, "we represent a minority but Literature is on our side…. There is no need to bore ourselves with this rubbish." But this maneuver left him even more vulnerable. The masses don't buy and certainly don't...