The handsome Vintage Internationals edition of Nabokov's Ada, or, Ardor--an extended riff on alternate-world and time theories and a key early example in the retro-futuristic subgenre of science fiction that years later came to be known as steampunk--would look out of place in the science-fiction section, with the blue-foil lettering, the starships, the furry-faced aliens, the electron-starred vistas of cyberspace.