Most science fiction and fantasy novels have a breaking point past which they would strain suspension of disbelief past bearing. Too many big ideas that don’t quite fit together, too much weirdness to process. Too many boundaries crossed for the fictional world to seem real. Good novels don’t get to that point. Great ones get close without crossing over.
Iain M. Banks’s novels of the Culture don’t actually seem to have that breaking point to begin with. Banks created a universe where the unbelievable and astonishing are part of the world, and suspension of disbelief isn’t needed because believing a constant stream of unbelievable worldbuilding is, in fact, part of the worldbuilding. From giant self-contained, sentient ships with too-whimsical names (the GSV Congenital Optimist) to characters existing in two places at once because cloned doppelgangers are a matter of course to far-out technology and extreme cultures and … actually, a list can’t contain the weirdness and joy of these books.
Use of Weapons isn’t the first of the Culture books I read. (That would be The Player of Games.) But it’s the one that, in Emily Dickinson’s phrasing, took the top of my head off. It’s the one I learned the most from.