The Expanse series is a science fiction series written by James S.A. Corey (a pen name for authors Daniel Abraham and Ty Franck). It is set in a future where humanity has colonized the solar system and is divided into political factions. The story follows a diverse cast of characters, including a detective, a spaceship captain, and a politician, as they navigate the complex web of power struggles and conspiracies that threaten to plunge humanity into war. The Expanse series is known for its realistic portrayal of space travel and its exploration of social and political issues.