Strata is a comic science fiction novel by Terry Pratchett. Published in 1981, it is one of Pratchetts first novels and one of only two science fiction novels he has written, the other being The Dark Side of the Sun. Although it takes place in a different fictional universe and is more science fiction than fantasy, it could be said to be a kind of prequel to the Discworld novels, as it also features a flat earth similar to Discworld.
The plot is modelled on (or parodies) that of the novel Ringworld by Larry Niven. Three intelligent beings - Kin Arad, a human, Marco, a kung, and Silver, a shand - are led to a flat earth, apparently artificially created and modelled after medieval views of the universe. After their ship is being hit by an orbiting "planet", they are forced to land on it. A return from the flat earth seems impossible unless they are able to find its mysterious builders. It turns out that this world is indeed modelled closely on the medieval earth - with the exception of its aburd cosmology and the fact that "magical" creatures and objects actually exist on it. All of this is supported by highly advanced and sophisticated technological systems - but as they lack maintanence, they are beginning to fail and the flat earth threatens to fall apart...
