FANTASY author Terry Pratchett has died having had Alzheimer's disease for eight years.
he much-loved author of the Discworld series was 66.
"The world has lost one of its brightest, sharpest minds," said Larry Finlay of his publishing company, Transworld.
Best known for the fantastical series, Mr Pratchett wrote more than 70 books over his lengthy career. He was first diagnosed with Alzheimer's in 2007, but continued writing, completing his final book last summer.
The author died at home "with his cat sleeping on his bed, surrounded by his family," Mr Finlay said.
"In over 70 books, Terry enriched the planet like few before him," he added.
"As all who read him know, Discworld was his vehicle to satirize this world: He did so brilliantly, with great skill, enormous humour and constant invention.
Mr Pratchett "fundamentally changed" the way dementia will be seen and understood forever, the chief executive of the Alzheimer's Society Jeremy Hughes has said.
Mr Pratchett spent a number of years working at Trinty College Dublin. In 2010 he joined the staff as an adjunct Professor in the School of English.
He was diagnosed with posterior cortical atrophy, a rare form of Alzheimer's disease, and became a passionate advocate for the right to die. He published his first novel, 'The Carpet People', in 1971 but his career as a novelist really took off after the publication of the first Discworld book, 'The Colour Of Magic', in 1983.
His books sold millions of copies worldwide and were translated into more than 30 languages.
He created an imaginary world - Discworld - disc-shaped (obviously), resting on the back of four gigantic elephants, which are themselves standing on an enormous interplanetary turtle - it was fantasy in the classic mould; fantasy with a sharp, wild sense of humour, and a sly line in social commentary, but fantasy none the less.
There were trolls and dragons, barbarian warriors and implausibly breasted Amazons in scanty armour, and wizards with staffs with knobs on the end; it took these tropes and subverted them, but that was its source material. But as the series - and its author - have matured, it has changed.
The great city of Ankh-Morpork, the scene for many of the stories, has slowly turned from a Dungeons & Dragons place of rogues and thieves brawling in taverns, into a fantasy mirror of London.
It become less about magic, and more about people, and ingenuity, and technology. He learnt this love of dangerous machinery and fancy gadgets from his father, growing up in Beaconsfield, a small town to the west of London.
His mother, meanwhile, helped him with book learning. "I wasn't particularly interested in books," he said in an interview.
"And my mum, God bless her, she rolled up her sleeves and gave me a penny per page, and it worked beautifully. I think she only gave me about thruppence, because the third book was 'The Wind in the Willows'."
He was so enthused after this, she no longer needed to pay him. He spoke, often, of how his time on local newspapers made him.
He started at 16, in high dudgeon at his headmaster: "On my last day at the school, I left all my stuff behind and phoned up the editor of a local newspaper. He actually used some cliché like, 'I like the cut of your jib, young man', or something."
It is the stuff of legend that he saw his first dead body the next day, "work experience really meaning something in those days", as he put it in his author's bio in his books.
"Truthfully, without over-egging it, as I often do," he says, "the library - where he worked part-time - and journalism, those things made me who I am."
He made a BBC documentary, 'Choosing to Die', which followed a man called Peter Smedley's decision to go to Switzerland's Dignitas clinic to be helped to commit suicide.
"Frankly, Mr Smedley would probably be with us now, if he hadn't had to go to Switzerland to do it. And that's why I hate the people who try to get in the way of this," he said, getting genuinely angry. (© Daily Telegraph, London)