Dr Jack Cohen is an internationally-known reproductive biologist, and lives in Newent, Gloucestershire. Jack has a laboratory in his kitchen, helps couples get pregnant by referring them to colleagues, invents biologically realistic aliens for science fiction writers and, in his spare time, throws boomerangs. Jack, who has more letters to his name than can be repeated here, writes, lectures, talks and campaigns to promote public awareness of science, particularly biology. He is mostly retired.

Terry Pratchett was the acclaimed creator of the global bestselling Discworld series, the first of which, The Colour of Magic, was published in 1983. In all, he was the author of over fifty bestselling books which have sold over 100 million copies worldwide. His novels have been widely adapted for stage and screen, and he was the winner of multiple prizes, including the Carnegie Medal. He was awarded a knighthood for services to literature in 2009, although he always wryly maintained that his greatest service to literature was to avoid writing any.

www.terrypratchettbooks.com