Book of Numbers (Random House), the new book by Joshua Cohen, is the first novel I can think of that manages to be both auto-fictional and hysterically realistic at the same time. This feat of genre-straddling ambition speaks both to Cohen’s enormous talent and to his continuing faith in the possibilities of the novel. As in an auto-fiction, this is a book by a writer called Joshua Cohen about a writer called Joshua Cohen, though how close the fictional Cohen is to his creator remains impossible to know. Both grew up on the Jersey Shore in the 1980s, and each is the author of a big book about a Jewish subject: The real Cohen wrote Witz, a 1,000-page fantasia about the end of American Jewry; while the fictional Cohen wrote a family memoir about his mother, a Holocaust survivor. These similarities are enough to pique the kind of interest that—as David Shields has written in Reality Hunger—only arises when the reader is unsure how much of what he is reading is truth and how much fiction. Adam Kirsch, tablet.