Nessus also recruits the Kzin Speaker-to-Animals and Teela Brown, a young human woman who becomes Louis's lover, for the rest of the ship's crew.

It has a habitable inner surface (equivalent in area to approximately three million Earths), a breathable atmosphere, and a temperature optimal for humans.

When the crew completes its mission, as payment they will be given the starship they used to travel to the puppeteer world; it is about 1000 times faster than any human or Kzinti ship.

The vessel collides with a strand of shadow-square wire and crash-lands near a huge mountain, which is called "Fist-of-God" by the first natives they speak with.

The fusion drive is destroyed, so they set out to find a way to get the Lying Bastard off the Ringworld and use the undamaged hyperdrive to return home.

There, they meet Halrloprillalar Hotrufan ("Prill"), a former crew member of a ship that had brought back goods from worlds abandoned by the Ringworld builders.

Louis surmises that a mold inadvertently brought back by a ship like Prill's mutated and broke down the superconductors vital to the Ringworld civilization, causing its fall.

Algis Budrys found Ringworld to be "excellent and entertaining ... woven together very skillfully and proceed[ing] at a pretty smooth pace."

While praising the novel generally, he faulted Niven for relying on inconsistencies regarding evolution in his extrapolations to support his fictional premises.

"[4] In addition to the two aliens, Niven includes a number of concepts from his other Known Space stories: The opening chapter of the original paperback edition of Ringworld featured Louis Wu teleporting eastward around the Earth in order to extend his birthday.

Moving in this direction would, in fact, make local time later rather than earlier, so that Wu would soon arrive in the early morning of the next calendar day.

One major one was that the Ringworld, being a rigid structure, was not actually in orbit around the star it encircled and would eventually drift, ultimately colliding with its sun and disintegrating.

"Ringworld" has become a generic term for such a structure, which is an example of what science fiction fans call a "Big Dumb Object", or more formally a megastructure.

In the Paramount+ series Star Trek: Lower Decks season 4, episode 3, "In the Cradle of Vexilon", a Ringworld-like world is prominently featured.

In 2017, Paradox Interactive added a DLC called "Utopia" to their game Stellaris,[8] allowing the player to restore or build ringworlds.

In 2021, Mobius Digital added a DLC called "Echoes of the Eye" to their game Outer Wilds,[9][non-primary source needed] which allows the player to explore a hidden, abandoned ringworld and determine what happened to its inhabitants.

This proposed four-hour miniseries was being written by Michael R. Perry and would have been a co-production between MGM Television and Universal Cable Productions.