From Williams (Conventions of War, 2005, etc.), a far-future science-fiction yarn that employs sword-and-sorcery trappings to investigate philosophical questions.
Thanks to native ingenuity and the computing power of an array of several planet-sized artificial intelligences orbiting Earth, humanity has consciously avoided a technological singularity; instead, wormhole engineering offers access to limitless artificial worlds, and nobody dies permanently—you simply resurrect your last memory back-up in a cloned body. Aristide, a computer scientist turned swordsman, perpetually amused both at himself and the universe's ability to astonish, studies implied spaces, disregarded regions not specified but suggested by the subtleties of architecture and geometry. While exploring the artificial world Midgarth, carrying his wormhole-tipped sword and accompanied by the talking cat Bitsy—she's actually an avatar of the AI, Endora—Aristide stumbles across a warrior-cult led by needle-toothed alien priests armed with tiny wormhole weapons. Recognizing the signs of a vast and deadly plot, Aristide returns to his home in the orbiting habitat Topaz to discuss the matter with persons he can trust. The allies must act before a bad situation deteriorates into another Seraphim Plague or a full-blown Existential Crisis…and that isn't even the half of it.
An intelligent, delicate and precise novel of real depth: a pleasure to read, an undertaking to savor.