Terry Pratchett, a treasure of a writer, a gem of a human being, and a credit to our species, has died, far too soon, at the age of 66.

Pratchett died at home, in bed, surrounded by his family and with his cat. He was diagnosed with early-onset Alzheimer's in 2007, and has since been a tireless advocate for the right to die with dignity, as well as a major donor to Alzheimer's research.

Pratchett continued to produce brilliant books after his diagnosis, most recently the important Raising Steam, which, more than any of the other Discworld books, explored the intrinsic "magic" wrought by technology on its advocates, and worked through technology's discontents.

I'm deeply saddened by Pratchett's death, even though I, like his other fans, had so long to get used to the idea that he would only be with us for a short time. The Discworld books are some of my truest friends. I've read many of them dozens of times, and always find new things to love in them.

I interviewed Pratchett last year on the occasion of the reissue of his first novel, The Carpet People, which he wrote at the age of 17. He was gentlemanly and fascinating, something that many of his interlocutors and fans have noted, but as Neil Gaiman reminds us: the thing that kept Terry Pratchett going wasn't his sweet nature, it was his anger:

There is a fury to Terry Pratchett's writing: it's the fury that was the engine that powered Discworld. It's also the anger at the headmaster who would decide that six-year-old Terry Pratchett would never be smart enough for the 11-plus; anger at pompous critics, and at those who think serious is the opposite of funny; anger at his early American publishers who could not bring his books out successfully.

The anger is always there, an engine that drives. By the time Terry learned he had a rare, early onset form of Alzheimer's, the targets of his fury changed: he was angry with his brain and his genetics and, more than these, furious at a country that would not permit him (or others in a similarly intolerable situation) to choose the manner and the time of their passing.

And that anger, it seems to me, is about Terry's underlying sense of what is fair and what is not. It is that sense of fairness that underlies Terry's work and his writing, and it's what drove him from school to journalism to the press office of the SouthWestern Electricity Board to the position of being one of the best-loved and bestselling writers in the world.

You can donate to The Research Institute for the Care of Older People in Pratchett's memory.

It is with immeasurable sadness that we announce that author Sir Terry Pratchett has died at the age of 66.

(Image: Terry Pratchett's Authoring Hat – Author Terry Pratchett speaks at Brisbane Grammar School, Spring Hill, Brisbane, Queensland, Australia 070214, David Jackmanson, CC-BY)