Betrayer of Worlds

Betrayer of Worlds is a science fiction novel by American writers Larry Niven and Edward M. Lerner, set in the Known Space series. It is a sequel to their previous novels Fleet of Worlds, Juggler of Worlds, and Destroyer of Worlds. Set 70 years before Ringworld, it features returning character Nessus, a young Louis Wu, and the rapidly evolving Gw'oth civilization posing a potential threat to the puppeteer Concordance.