The British fantasy author died today and his publisher said he faced the disease "publicly and bravely"
UK fantasy author Terry Pratchett has died aged 66.
His publisher confirmed today he passed away after a long battle with Alzheimer's disease.
Larry Finlay, managing director at Transworld Publishers, said: "I was deeply saddened to learn that Sir Terry Pratchett has died. The world has lost one of its brightest, sharpest minds.
"In over 70 books, Terry enriched the planet like few before him. 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.
"Terry faced his Alzheimer's disease (an 'embuggerance', as he called it) publicly and bravely. Over the last few years, it was his writing that sustained him. His legacy will endure for decades to come.
Mr Finlay added: "We ask that the family are left undisturbed at this distressing time."
Terry died today aged 66
Sir Terry's publisher released a statement this afternoon after it was announced Terry had died aged 66.
Larry Finlay, managing director at Transworld Publishers, said: "I was deeply saddened to learn that Sir Terry Pratchett has died. The world has lost one of its brightest, sharpest minds.
"In over 70 books, Terry enriched the planet like few before him. 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.
"Terry faced his Alzheimer's disease (an 'embuggerance', as he called it) publicly and bravely. Over the last few years, it was his writing that sustained him. His legacy will endure for decades to come.
"My sympathies go out to Terry's wife Lyn, their daughter Rhianna, to his close friend Rob Wilkins, and to all closest to him."
He went on to say Terry passed away in his home, with his cat sleeping on his bed surrounded by his family on 12 March 2015.
Mr Finlay added: "Diagnosed with PCA in 2007, he battled the progressive disease with his trademark determination and creativity, and continued to write.
"He completed his last book, a new Discworld novel, in the summer of 2014, before succumbing to the final stages of the disease.
"We ask that the family are left undisturbed at this distressing time."
Daughter pays tribute
Terry's daughter Rhianna has paid tribute to her talented father on Twitter.
The games writer and journalist posted the same tweets as the ones on his official account, writing on the social media site: "AT LAST, SIR TERRY, WE MUST WALK TOGETHER.
"Terry took Death’s arm and followed him through the doors and on to the black desert under the endless night."
She then shared a link to the statement from his publisher and added: "The End."
Sir Terry Pratchett and Dignity in Dying
Sir Terry Pratchett part-funded the Commission on Assisted Dying (2010-2011) which was run by independent think-tank Demos.
The commission led to Lord Falconer tabling The Assisted Dying Bill, which is currently in the House of Lords and won two major votes at Committee Stage in January.
Dignity in Dying campaigns for greater choice, control and access to services at the end of life.
It advocates providing terminally ill adults with the option of an assisted death, within strict legal safeguards, and for universal access to high quality end-of-life care.
Dignity in Dying has over 25,000 supporters and receives its funding entirely from donations from the public.
Chief executive pays tribute
Sarah Wootton, Chief Executive of Dignity in Dying, paid tribute to Terry today.
In a statement, she said: "I am saddened to hear of the death of Dignity in Dying Patron Sir Terry Pratchett and our thoughts are with his family and close friend Rob Wilkins.
"Terry was a committed campaigner who did an enormous amount to bring assisted dying for terminally ill people to the public's attention.
"He accompanied Peter Smedley to Dignitas in a landmark BBC documentary which showed how terminally ill people are currently being forced to travel abroad to control their deaths.
"Sir Terry was fond of saying, 'It's time we learned to be as good at dying as we are at living" and his brave approach to confronting issues of death, including his own, was a heartfelt demonstration of dignity."
Top quotes from Terry
The literary world is today mourning the death of celebrated storyteller Terry Pratchett.
Here are a few of his most memorable quotes throughout his career:
"The whole of life is just like watching a film. Only it's as though you always get in ten minutes after the big picture has started, and no-one will tell you the plot, so you have to work it out all yourself from the clues."
"It’s not worth doing something unless someone, somewhere, would much rather you weren't doing it."
"If you don't turn your life into a story, you just become a part of someone else’' story." – from The Amazing Maurice and His Educated Rodents.
"I have no use for people who have learned the limits of the possible."
David Cameron: "He fearlessly campaigned"
Prime Minister David Cameron today said he was sad to hear of Sir Terry's death.
He said: "His books fired the imagination of millions and he fearlessly campaigned for dementia awareness."
Health Secretary Jeremy Hunt also paid tribute to the fantasy author, who passed away after a long battle with Alzheimer's disease.
"Sad 2 hear of loss of inspirational Alz campaigner Sir Terry Pratchett. His proud legacy: massively more understanding about dementia," he posted online.
Fans pay tribute to the author
Fans have taken to Twitter to pay tribute to the best-selling author.
Waterloo Road actor and DJ Zebb Finn Dempster wrote on the site: "Rest in peace Sir Terry Pratchett, thank you for brightening my childhood with your work, the world has lost a truly magical man."
Canadian author Guy Gavriel Kay also added: "Oh, this is a terrible loss. Deeply saddened to learn Sir Terry Pratchett has died. We are diminished by this death."
Comedian Ricky Gervais also quoted the writer, tweeting: "It's not worth doing something unless someone, somewhere, would much rather you weren’t doing it." RIP the brilliant Terry Pratchett."
Sir Terry's success
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, also the 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 1 million (£500,000) to the Alzheimer's Research Trust.
Choosing To Die documentary
Speaking in 2011 documentary Choosing To Die, Sir Terry spoke frankly to those with long term illnesses.
In the video, the writer and author discusses the options of taking one's own life with one man.
Multiple Sclerosis sufferer Andrew Colgan, talked openly about his options.
"I would like to have a death that is comfortable and relatively painless, I am really of the opinion that, 'Why shouldn't I?'" he said, as Pratchett asked about the end.
Terry Pratchett: Choosing to Die was a 2011 one-off television documentary produced by KEO North for BBC Scotland on the subject of assisted suicide.
In a frank and personal documentary, author Sir Terry considered how he might choose to end his life. Diagnosed with Alzheimer's in 2008, Terry wanted to know whether he might be able to end his life before his disease takes over.
Travelling to the Dignitas Clinic in Switzerland, Terry witnessed first hand the procedures set out for assisted death, and confronts the point at which he would have to take the lethal drug.
Fans mourn Terry's death
The literary world is mourning the death of Sir Terry Pratchett today who lost his battle with Alzhiemer's disease.
The 66-year-old best-selling author, who completed his last book, a new Discworld novel, last year, succumbed to the final stages of the disease this week.
Larry Finlay, managing director at Transworld Publishers, said: "I was deeply saddened to learn that Sir Terry Pratchett has died. The world has lost one of its brightest, sharpest minds.
"In over 70 books, Terry enriched the planet like few before him. 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.
"Terry faced his Alzheimer's disease (an 'embuggerance', as he called it) publicly and bravely. Over the last few years, it was his writing that sustained him. His legacy will endure for decades to come."
Prime Minister David Cameron paid tribute to the fantasy writer today and said he was sad to hear of his death.
He took to Twitter and posted: "His books fired the imagination of millions and he fearlessly campaigned for dementia awareness."
Terry's daughter Rhianna also posted the final messages shared on his own Twitter account, including: "AT LAST, SIR TERRY, WE MUST WALK TOGETHER.
"Terry took Death’s arm and followed him through the doors and on to the black desert under the endless night."
She then shared a link to the statement from his publisher and added: "The End."