The knight of the thoughtful page has gone before. I've always thought of him as a young man, perhaps because I was a young man when I first enjoyed reading his books. Or perhaps some authors remain genuinely young at heart, and it shows in their writing.
I haven't read every one of the dozens of Discworld novels, but I've been an admirer of Terry Pratchett's work since the early days. His sf books, Strata and The Dark Side of the Sun, are well worth seeking out. But it is of course for his fantasy that he's best known. His books are full of supernatural imagery and ideas, as well as characters who use magic (or are used by it).
What I admired most about him, I think, is that his imagination never took him far from a very English and humane view of life. He infused his work with humour and compassion, and never forgot that his readers were intelligent human beings who would 'get it'. He will be greatly missed.