Have you seen the TV series, Castle? It's a pleasant ABC detective show in which a mystery writer teams up with a real detective and solves cases. Somebody had the bright idea of publishing mystery novels under the name of the fictional character, Richard Castle.
The first one, "Naked Heat," sold more than 200,000 and got onto the New York Times best-seller list. The new one, "Heat Wave" (do you detect a pattern here?) looks like it will better those numbers.
I don't know the moral of the story for us writers. Maybe it's to get your own TV series or ghost for a character who does. Hmm, maybe the Simon Cowell Mysteries (the main one is what does he do with all that money?).
(To get tips on writing your own book, get mine: Your Writing Coach, published by Nicholas Brealey and available from Amazon and other online and offline booksellers. Why not ask your favorite local bookshop to order it for you?)