
Ringworld
Description
1970: Ringworld
1980: The Ringworld Engineers
1996: The Ringworld Throne
2004: Ringworld's Children
The core series was developed with three side series of prequels set in the same Ringworld universe, and written in collaboration:
1988–2009: Man-Kzin Wars (by various edited by Niven)
2007–2010: Fleet of Worlds (by Niven and Edward M. Lerner)
2010-2011: Juggler of Worlds (by Niven and Edward M. Lerner)