Each year, BookFinder.com puts out a list of the top 100 most searched for out of print book titles from the previous 12 months. For 2013, the top three slots are occupied by two people. One wrote under his own name for one and under a pseudonym for the other; the other maybe should have adopted an alias, but never would have.
The latter, in the Number One slot, is Sex by Madonna, which perhaps earns its place at the top for reasons other than the subject matter:
The book itself is spiral bound and actually quite fragile making fine copies relatively rare; copies still found in their Mylar wrapping sheet command an extra premium… After the book’s initial, albeit large, print run Sex has never since been reproduced as Madonna has very typically moved on from this phase of her career. As such one can assume that Sex will probably remain out of print indefinitely.
I’m betting most of you can guess the author of the next two.