It is unfashionable, politically grossly incorrect, to buy into the "clash of civilizations" understanding of the relationship between Islam and the West. But it becomes more and more difficult to resist the idea. So we repair to the notion of a clash of civilizations, which provides us with a convenient cover: "They" are fundamentally different from us; what more does one need to know? Much more, as it turns out. One needs to know how it is that so many of America's Muslims seem so readily to have absorbed American values of pluralism and tolerance. The world's Muslims are not a 1.5 billion-person mob, even if that is how many in the West see them; they contain enormous internal variety.