Gene Wolfe also wrote a book called The Castle of the Otter, which began life as an announcement that he had a book by that title in press, run by Locus which had somehow garbled the actual title, The Citadel of the Autarch. Wolfe then decided to make this true.

The urge to make such things true is quite a strong one, I think. (I seem to recall that Armand Hammer bought Arm and Hammer largely because the universe wouldn't feel quite "right" unless he did.) Also, a book title that's mentioned in another book or thrown up by happenstance like that calls out to be written, if not by the author then by a fanficcer, and has something of a Pandora's box aura until that happens.