Sir Terry Pratchett

born April 28 1948,

died March 12 2015

SIR TERRY PRATCHETT, who has died aged 66, was one of Britain's most popular and successful novelists whose comic fantasies, many of them set in Discworld, attracted a devoted following; in later life, after he had been diagnosed with a rare form of early-onset Alzheimer's disease, he became known to a wider audience through campaigning and television documentaries, about both his disease and the right to euthanasia.

Pratchett was the best-selling UK author of the 1990s and in the first decade of this century, second only to J.K. Rowling; his hardback sales by themselves accounted for some 3.5% of the total market for hardback fiction. He sold well over 75 million copies of his books in almost 40 languages and his work was the subject of numerous conventions at which fans (many in costume) would meet to share their enthusiasm for his work. A further measure of his popularity was that he was the most shoplifted author in the UK.

This popularity, and the fact that he wrote both fantasy and comedy, led to his work being belittled by much of the literary establishment for many years - an early academic collection devoted to his work defiantly bore the title Terry Pratchett: Guilty of Literature. But in later years, his books began to be the subject of serious study, and Pratchett himself received nine honorary doctorates and became an adjunct Professor at Trinity College Dublin's English department.

Terence David John Pratchett was born on April 28 1948 at Beaconsfield in Buckinghamshire and after passing the 11-plus was admitted to John Hampden Grammar School in High Wycombe but, feeling "woodwork would be more fun than Latin" switched to High Wycombe Technical High School. He preferred to list his education as Beaconsfield Public Library in Who's Who.

He developed an interest in astronomy, collecting and ham radio (his father was an amateur radio fan) and these led him to science fiction. At 13, he published his first story "The Hades Business" in the school magazine; two years later it was printed in Science Fantasy, on the proceeds of which he bought a typewriter. He wrote several more stories while still at school and decided to become a journalist and in 1965 abandoned his A-levels to join the Bucks Free Press.

His duties there included writing a column of stories for children, some 60 in all, which later became his first book, The Carpet People, and he completed the NCTJ course and acquired his A-level in English on day release. He also interviewed Peter Bander van Duren, a director of the publishing firm Colin Smythe Ltd, to whom he mentioned The Carpet People. The firm published it in 1971, to little fanfare, launching it in the carpet department of Heal's furniture shop in London.

By this time Pratchett was married, and working at the Western Daily Press, but the following year he returned to his first paper as a sub, before joining the Bath Evening Chronicle in 1973. His second book, The Dark Side of the Sun (1976), was an apparently straightforward science fiction novel which offered a pastiche of many of the themes of Larry Niven's Ringworld, dealing with probability and a defunct race of highly-advanced beings called the jokers. The home planet of the hero, in a typical touch, was called Widdershins. Many similar themes were taken up in Strata (1982), but neither book fared well commercially.

Pratchett had moved from journalism to work as a press officer for the Central Electricity Generating Board in 1980, where he was responsible for three nuclear power stations. He remembered a phone call from his boss at 6.30am which began: "Have you heard the news? Well, it's not as bad as it sounds..."

New English Library, who had been licensed by Colin Smythe to publish the second and third novels but had just been bought by Hodder & Stoughton, were glad to drop Pratchett, and Colin Smythe brought out the first of the Discworld books, The Colour of Magic in hardback in 1983. In 1985, it was published in paperback by Corgi and serialised on Radio 4's Women's Hour.

He followed it with a sequel, The Light Fantastic and Equal Rites, a separate novel in the same universe. By the fourth Discworld book, Mort, he was able to give up his day job, having been signed (as their first fantasy author) by Gollancz, which also bought hardback rights to the earlier books. Smythe became Pratchett's literary agent.

There then followed an unending stream of novels, in which Pratchett expanded Discworld's horizons and introduced a host of comic characters, often parodies of well-known fictional figures, and whose names were frequently puns. He employed the bathetic footnote to comic effect and sent up all manner of subjects. He tackled the police (Guards! Guards!), cinema (Moving Pictures), the post office (Going Postal), journalism (The Truth), banking (Making Money) and the railways (Raising Steam), amongst sideswipes at almost any target out of which he could get a funny line.

As Discworld became a phenomenon, there were companion volumes on its geography, history, science and cuisine. Board games, video games, graphic novels, television adaptations (for Sky, with David Jason) and other off-shoots followed.

Pratchett's other work included a satire on the apocalypse co-written with Neil Gaiman, Good Omens (1990); a parallel earth trilogy written with Stephen Baxter, and a collection of his short fiction, A Blink of the Screen (2012) and of his non-fiction, A Slip of the Keyboard (2014). He also wrote a number of children's novels featuring a boy called Johnny Maxwell; his first Discworld book for children, The Amazing Maurice and his Educated Rodents won the 2001 Carnegie Medal. In 2010 he won the World Fantasy Lifetime Achievement Award.

He was appointed OBE in 1998 and knighted for services to literature in the 2009 New Year's Honours. An asteroid was named after him.

Pratchett continued to work after being diagnosed with Alzheimer's disease in 2007, speaking out on the subject, making a documentary - and a subsequent programme on assisted dying - and giving substantial support, financial and personal, to charities and research programmes dealing with the disease.

A softly-spoken figure, usually clad in an outsized fedora or Stetson, Pratchett was a much-loved figure at conventions and book signings (which frequently lasted for hours and attracted thousands). He lived near Salisbury in Wiltshire, where he built an observatory in his garden.

He is survived by his wife Lyn and his daughter Rhianna, who is also a writer.