The sci-fi author is dead at 91.

I'm kind of ashamed to say that, though Farmer has written science fiction for 50 years, I've only read three of his books: Tarzan Alive, about the history of Tarzan, Doc Savage: His Apocalyptic Life, about the history of Doc Savage, and Venus on the Half-Shell, which Farmer wrote under the pseudonym Kilgore Trout. Kurt Vonnegut gave Farmer his blessing to use his Trout alter ego—Farmer nearly wrote a whole series of Kilgore Trout novels, but the two had a disagreement and the series was scrapped.

The thing that strikes me as the most notable about Farmer's passing is that a giant piece of publishing history—especially the part pertaining to sci-fi pulp—is now gone forever.