The Dark Side of the Sun is a science fiction novel by Terry Pratchett, first published in 1976. It is similar to the work of Isaac Asimov. According to Don D'Ammassa, both this and Pratchett's 1981 sci-fi novel Strata spoof parts of Larry Niven's Ringworld. The holiday of Hogswatch, which appears in the Discworld books, is celebrated by the characters in The Dark Side of the Sun.