The Science of Discworld is a 1999 book by novelist Terry Pratchett and popular science writers (and University of Warwick science researchers) Ian Stewart and Jack Cohen. Three sequels, The Science of Discworld II: The Globe, The Science of Discworld III: Darwin's Watch, and The Science of Discworld IV: Judgement Day, have been written by the same authors. Following publication of the first book in 1999 Terry Pratchett made both Jack Cohen and Professor Ian Stewart "Honorary Wizards of the Unseen University" at the same ceremony at which the University of Warwick gave Terry Pratchett an honorary degree.The book alternates between a typically absurd Discworld story and serious scientific exposition after each chapter. The cover of the book, designed by Paul Kidby, is a parody of the 1768 painting "An Experiment on a Bird in the Air Pump" by Joseph Wright of Derby. Source: Wikipedia (en)