Numenera: Beneath the Monolith - Rules of Play says:
The Ninth World is the setting of Monte Cook’s multiple-award-winning Numenera RPG. Beneath the Monolith brings this critically acclaimed world to 5e. Explore the ruins of incomprehensible civilizations. Discover the numenera, ancient technologies so advanced that most people think they’re just magic. Encounter creatures weird, fierce, and dangerous. Open doors to new worlds and alternate dimensions. And, perhaps, unlock some of the mysteries of the prior worlds.