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 . 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 systemss 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 Known Space.
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.