This week I thought I'd get a little meta on y'all. Instead of talking about fictional mysteries, I'm going to talk about real-world unsolved mysteries involving authors and literature.
"Theophanes" has done a good job summarizing the three biggest mysteries in literary history: the death of Edgar Allan Poe, the disappearance and death of Ambrose Bierce, and the ten-day disappearance of Agatha Christie. Read all about those here.
In "The Unicorn and the Wasp," Doctor Who fans received a possible explanation for what happened to Christie. (It won't surprise you to hear that aliens and time travel are involved.) And, guess what, Edgar Allan Poe's death figures in two Doctor Who novels published in 2004: The Algebra of Ice and The Deadstone Memorial. That leaves Ambrose Bierce's story available, BBC writers -- you should get on that!