Planescape Books

“Beyond those somewhat anchored fantasy settings are the wild-eyed and the wahoo worlds. This is by no means pejorative, as these include some of my personal favorites, but it is meant to show that there are high-concept, love-’em-or-hate-’em sorts of settings. Call them worlds of pure chaos, places where anything goes and where the usual rules do not apply. They are not meant to be realistic, and indeed that is their appeal. They are settings unmoored from reality and operating by rules of your design—but these settings do have rules. To provide some examples, think of places like China Mieville’s Bas Lag, Pratchett’s Disc World, Frank Baum’s Oz, David “Zeb” Cook’s Dark Sun and Planescape, Keith Baker’s Eberron, Jim Ward’s Gamma World, NCSoft’s Guild Wars, Andrew Leker’s Jorune, Michael Moorcock’s Melnibone, Jeff Grubb’s Spelljammer, and Blizzard’s World of Warcraft. These are places where truly Weird Shit happens, with different rules of physics, alien landscapes, magical wastelands, alien gods, mutants, and cosmologies. It’s fun to go out on the edge, and fantasy is always exploring strange places like this. These are the high-wire acts of worldbuilding. They take creative risks, not always successfully, and they endure a higher degree of mockery than the real fantasies or anchored fantasies do because of those creative risks. They also attract a loyal following who love that particular flavor of weird. Just ask any Planescape fan.”
― Wolfgang Baur, Complete Kobold Guide to Game Design