Sir Terry Pratchett, British fantasy author and satirist best known for his 40-volume series of Discworld novels, which included The Colour of MagicHogfather and Snuff, passed away today after an eight-year battle with Alzheimer's disease.

The disease seemed at first to be little more than a road bump for Pratchett, who continued to write books all the way up to his death. His most recent work was published last summer, with another set to be released this fall. As recently as 10 years ago he was Britain's second most popular author, surpassed only by J.K. Rowling at the height of the Harry Potter craze.

Pratchett published more than 70 books over his career, and was made an officer of the Order of the British Empire in 1998 for his services to literature. In 2009, just two years after his diagnosis of early-onset Alzheimer's, Pratchett was knighted by the Queen.

During the years leading up to his death, Pratchett was an ardent advocate both for Alzheimer's research, making significant donations to the Alzheimer's Research Trust, and for voluntary assisted suicide in the event of a terminal diagnosis. Despite that, there is no indication that Pratchett's death was anything but natural.

Pratchett's Twitter account announced his death with a series of tweets in the form of a narrative involving one of his most enduring and beloved characters, the personification of Death:

He will be missed.