Slaughterhouse-Five, by Kurt Vonnegut (49,459 words):Read about the other entries on the list.
Vonnegut’s masterwork packs more ideas—time travel, gender politics, a potent antiwar allegory, er, aliens putting people on display in zoos—than most novels twice its length. (Vonnegut’s Cat’s Cradle would also fit nicely on this list, and is equally rich with weirdness.)
Slaughterhouse-Five also made Tom Lamont's top ten list of time travelers, Melissa Albert's list of six favorite fictional book nerds, Jon Ronson's five top list of books on madness, Charlie Yu's top ten list of time travel books, John Mullan's list of ten of the best aliens in science fiction, Charlie Jane Anders and Michael Ann Dobbs's list of twelve great stories to help you to cope with mortality, Sebastian Beaumont's top 10 list of books about psychological journeys, and Tiffany Murray's top ten list of black comedies.
Also see: Twenty of the best books under 200 pages.
--Marshal Zeringue