Perhaps his best-known work is
Ringworld (1970), which received Hugo, Locus and Nebula awards.
Niven is the author of numerous science fiction short stories and novels, beginning with his 1964 story "The Coldest Place" (which in the story was said to be the dark side of Mercury, which was thought to be tidally locked with the Sun at the time it was written but which ironically enough was found to rotate in a 2:3 resonance just months before the story was published).
Niven has also written scripts for various science fiction television shows, including the original Land of the Lost series and Star Trek: The Animated Series. One of his short stories, "Inconstant Moon", was adapted for an episode of the series The Outer
Limits.
A thinly disguised Niven appears as the character "Lawrence Van Cott" in the Greg Bear novel The Forge of God.
Many of Niven's stories take place in his Known Space universe, in which humanity shares the several solar systems nearest to Sol with over a dozen alien species, including species known as the Kzinti, and Pierson's Puppeteers, which are frequently central characters. The Ringworld trilogy is set in the Known Space universe.
Niven has also written a logical fantasy series set in The Warlock's Era, detailed in The
Magic Goes Away. There is a Magic: the Gathering card named Nevinyrral's Disk, which contains Larry Niven's name backwards. When tapped it destroys all creature, enchantment, and artifact cards in play, including itself. This is likely a reference to the Warlock's Disc from this series, which when activated drains all magic from a region by using it up with an open-ended enchantment.
In recent years, most of his writing has been in collaboration with Jerry Pournelle and/or Steven Barnes.
There are those who think that Niven numbers may have been named in his honor, but despite his popularity and mathematical background, they're actually named for Ivan M. Niven.
