Ringworld is a 1970 science fiction novel by Larry Niven, set in his Known Space universe and considered a classic of science fiction literature. Ringworld tells the story of Louis Wu and his companions on a mission to the Ringworld, an enormous rotating ring, an alien construct in space 186 million miles in diameter. Niven later wrote three sequel novels and then cowrote, with Edward M. Lerner, four prequels and a final sequel; the five latter novels constitute the Fleet of Worlds series. All the novels in the Ringworld series tie into numerous other books set in Known Space. Ringworld won the Nebula Award in 1970, as well as both the Hugo Award and Locus Award in 1971.

Laurence van Cott Niven is an American science fiction writer. His 1970 novel Ringworld won the Hugo, Locus, Ditmar, and Nebula awards. With Jerry Pournelle he wrote The Mote in God's Eye (1974) and Lucifer's Hammer (1977). The Science Fiction and Fantasy Writers of America gave him the 2015 Damon Knight Memorial Grand Master Award.