Terry Pratchett sold more than 70 million books
Sir Terry Pratchett, creator of the long-running Discworld series of comic fantasy novels, was among the most prolific and successful authors of his generation.
He sold 70 million books world-wide with translations into more 30 languages. In the 1990s he was Britain's best-selling author. He was, at the turn of the century, Britain's second most-read author, beaten only by J K Rowling creator of Harry Potter.
His first novel, The Carpet People, was published in 1971 and his first Discworld novel (The Colour of Magic) was published in 1983. At one point he held the dubious honour as the most shop-lifted author in Britain.
But health problems were to afflict him. In August, 2007, he was misdiagnosed as having suffered a stroke, but the following December he announced that he had been newly diagnosed with a very rare form of early-onset Alzheimer's disease which, he said, "lay behind this year's phantom stroke".
But he urged people to "keep things cheerful", adding: "We are taking it fairly philosophically down here" and predicting that he had time for "at least a few more books yet".
The following March he announced that he was donating £500,000 to the Alzheimer's Research Trust.
Terence David John Pratchett was born on 28 April, 1948 at Beaconsfield. He published his first short story at the age of 13, and later began work for the Bucks Free Press newspaper.
After various positions in journalism, he became press officer for the Central Electricity Generation Board in 1983, the year in which his first Discworld novel was published.
He gave up working for the CEGB in 1987, after finishing his fourth Discworld novel. His sales increased quickly, and many of his books occupied top places in the best-seller lists. He was the top-selling and highest-earning author in 1996.
He was well-known for wearing large black hats and his sartorial style was once described as "more that of urban cowboy than city gent".
He was an avid computer games player and collaborated in the creation of a number of game adaptations of his books.
In 1998, he was awarded an OBE for 'services to literature' and was knighted in 2009.
Receiving the honour at Buckingham Palace, he said multimillion-pound banker bonuses should be spent helping to treat dementia patients.
Sir Terry also described the 'furore' that greeted the announcement he was suffering from dementia but said it had helped raise awareness about the illness.
Dressed in a top hat and morning suit the writer said: "It would appear to me that me getting up and saying 'I've got Alzheimer's', it did shake people, you cannot help but notice it's in the news an awful lot.
"The thing about Alzheimer's is there are few families that haven't been touched by the disease.
"People come up to me and talk about it and burst into tears, there's far more awareness about it and that was really what I hoped was going to happen.
"Everybody thinks the Government should be doing more about everything but just think how many of the bonuses which are quite rightly being dragged off certain people, just think to what good causes they could be put - wouldn't that be a lovely thought?"
He also had many other awards to his name, including the British Books Award as the "Fantasy and Scientific Author of the Year" in 1994.
In addition, he was awarded honorary doctorates of literature by the Universities of Warwick, Portsmouth, Bath and Bristol.
His concern for the future of civilisation prompted him to install five kilowatts of photovoltaic cells (for solar energy) at his house near Salisbury. And his childhood interest in astronomy led him to build an observatory in his garden.