Halfway through Julian Barnes’s latest book, a woman named Jean explains to the author that not all his books have worked for her. “This hybrid stuff you do — I think it’s a mistake,” she says. “You should do one thing or the other.” Keen to defend himself and his methods, Barnes retorts: “I don’t mind you not liking my books, but you are mistaken if you think I don’t know exactly what I’m up to when I write them.”