Discworld is a comic fantasy book series written by the English writer Terry Pratchett, set on the fictional Discworld, a flat disc balanced on the backs of four elephants which, in turn, stand on the back of a giant turtle, Great A'Tuin. The books frequently parody, or at least take inspiration from J. R. R. Tolkien, Robert E. Howard, H. P. Lovecraft and William Shakespeare, as well as mythology, folklore and fairy tales, often using them for satirical parallels with current cultural, political and scientific issues. The series is extremely popular and more than 70 million copies have been sold, with translations made into 37 languages.
Since the first novel, The Colour of Magic (1983), 39 Discworld novels have been published as of September 2011. Pratchett, who suffers from Alzheimer's disease, has said that he would be happy for his daughter Rhianna to continue the series when he is no longer able to do so. The original British editions of the first 26 novels, up to Thief of Time (2001), had distinctive cover art by Josh Kirby; the American editions, published by Harper Collins, used their own cover art. Since Kirby's death in October 2001, the covers have been designed by Paul Kidby. Companion publications include six short stories (some only loosely related to the Discworld), three popular science books, and a number of supplementary books and reference guides. In addition, the series has been adapted for the theatre, as computer games, as music inspired by the series, and repeatedly for television.
Newly released Discworld books regularly top The Sunday Times best-sellers list, making Pratchett the UK's best-selling author in the 1990s, although he has since been overtaken by Harry Potter author J.K. Rowling. Discworld novels have also won awards such as the Prometheus Award and the Carnegie Medal. In the BBC's Big Read, four Discworld novels were in the top 100, and a total of fourteen in the top 200.