"Ringworld" is a science fiction novel by American author Larry Niven, first published in 1970. The novel is set in a future where humanity has colonized many worlds and encountered a variety of alien species.
The story follows a group of characters who are brought together to explore a mysterious object known as the Ringworld. The Ringworld is a massive artificial structure that encircles a star, and is home to a wide variety of alien species.
The protagonist of the novel is Louis Wu, a human who is recruited by an alien named Nessus to join a mission to explore the Ringworld. They are joined by Teela Brown, a young woman who has been selected for the mission because of her supposed "luck."
As the group explores the Ringworld, they encounter a variety of strange and dangerous creatures, and uncover secrets about the structure's origin and purpose. They also must confront their own personal demons and learn to work together in order to survive.
"Ringworld" is known for its imaginative world-building and complex characters. The novel has won numerous awards, including the Hugo, Nebula, and Locus awards for best science fiction novel of the year. It has also spawned several sequels and has had a significant influence on the genre of science fiction.