IT'S one of history's most important questions: Why did Europe and North America embrace democracy and thrive economically while countries elsewhere suffered oppression and stagnation? Leading U.S. sociologist Rodney Stark says many scholars purposely overlook the obvious answer: It was the spread of Christianity that made possible political and economic freedoms, modern science and resulting western advancement. Such is the Baylor University professor's contention in The Victory of Reason: How Christianity Led to Freedom, Capitalism and Western Success (Random House), one of the more provocative of recent books, whose vigorous prose reflects the author's one-time employment as a newspaper reporter....