The Pact Worlds are the beating heart of the Starfinder campaign setting, a solar system full of citizens both familiar and bizarre. From the cosmopolitan corridors of Absalom Station to the carnivorous jungles of Castrovel or the floating cloud-cities of the gas giant Bretheda, this hardcover rulebook is your guide to Starfinder's core worlds and civilizations, and the perfect place to launch any adventure. Inside, you'll find: In-depth gazetteers of the system's 14 major worlds, from high-tech Verces and the draconic empires of Triaxus to the necromantic wastleands of Eox or magical bubble cities floating on the surface of the sun. Each gazetteer features a detailed world map, residents and cultures, settlements and adventure locations, a unique theme to customize characters from that world, and more. New playable alien races, from undead Eoxians to Castrovellian plant-people. New starships, from the living vessels of the Xenowardens to sinister Hellknight dreadnoughts. A codex of themed NPC stat blocks to help Game Masters create vivid encounters. New archetypes for every class, including the Star Knight, Skyfire Centurion, and Divine Champion. Tons of new weapons, armors, spells, feats, magic items, technological gadgets, and more to help outfit your adventurers.