He had long expressed his desire to die by assisted suicide before the disease reached its critical point, a subject he poignantly explored in 2011's BBC documentary Terry Pratchett: Choosing to Die.
A statement from Pratchett's publisher said that the author passed away, "in his home, with his cat sleeping on his bed surrounded by his family on 12th March 2015."
Pratchett rose to fame in the 1990s with his Discworld books, a comic fantasy series that took place in the fictional Discworld, a flat disc balanced on the backs of four elephants which, in turn, stand on the back of a giant turtle, Great A'Tuin. By the end of his career, he had penned more than 70 books, including bestseller Good Omens, which he co-wrote with fellow fantasy author Neil Gaiman.
A lifelong friend of the author, Gaiman posted on his website that, "Thirty years and a month ago, a beginning author met a young journalist in a Chinese Restaurant, and the two men became friends, and they wrote a book, and they managed to stay friends despite everything. Last night, the author died… There was nobody like him. I was fortunate to have written a book with him, when we were younger, which taught me so much."
Also speaking of his death, Transworld Publishers' Larry Finlay said that the world had, “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 satirise 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."
Despite not being able to physically write. Pratchett continued to author by dictation. He completed his last book, a new Discworld novel, in the summer of 2014.
