Laurence van Cott Niven is an American science fiction author. His best-known work is Ringworld (1970), which received Hugo, Locus, Ditmar, and Nebula awards. His work is primarily hard science fiction, using big science concepts and theoretical physics.
Niven's most famous contribution to the SF genre is his concept of the Ringworld, a band of approximately the same diameter as Earth's orbit rotating around a star. The idea's genesis came from Niven's attempts to imagine a more efficient version of a Dyson Sphere, which could produce the effect of surface gravity through rotation. Given that spinning a Dyson Sphere would result in the atmosphere pooling around the equator, the Ringworld removes all the extraneous parts of the structure, leaving a spinning band landscaped on the sun-facing side, with the atmosphere and inhabitants kept in place through centrifugal force and 1000 mile high perimeter walls (rim walls). When it was pointed out to Niven that the Ringworld was dynamically unstable, in that once the center of rotation drifted away from the central sun, gravity would pull the ring into contact with the star, he used this as a plot element in the sequel novel, The Ringworld Engineers.
This idea proved influential, serving as an alternative to a full Dyson Sphere that required fewer assumptions (such as artificial gravity) and allowed a day/night cycle to be introduced (through the use of a smaller ring of "shadow squares", rotating between the ring and its sun). This was further developed by Iain M. Banks in his Culture series, which features about 1/100th ringworld–size megastructures called Orbitals that orbit a star rather than encircling it entirely. Alastair Reynolds also uses ringworlds in his 2008 novel House of Suns. The Ringworld-like namesake of the Halo video game series is the eponymous Halo megastructure/superweapon. It is one of the most visible influences of the Ringworld concept on popular culture.
Edited from Larry Niven on Wikipedia.