In Lionel Shriver's entertaining send-up of today's cult of exercise--which not only encourages better health, but now like all religions also seems to promise meaning, social superiority, and eternal life--an aging husband's sudden obsession with extreme sport makes him unbearable. After an ignominious early retirement, Remington announces to his wife Serenata that he's decided to run a marathon. This from a sedentary man in his sixties who's never...