Sex in fiction, like sex on a beach, ought to be a no-brainer. On the one hand, there's, well, sex, a source of mystifying pleasure and profundity that for most people rarely elicits any articulation other than a contented grunt, groan, or gasp. On the other hand, there's the novel, an artistic enterprise devoted to making verbal sense of mute experience. In theory, the setup seems the perfect illustration of the Reese's principle: two great tastes that taste great together.