Clarification/Follow-up by Jim.McGinness on 12/14/06 10:14 am:
I was being serious. It's a literary quote (Lewis Carroll) and, to a lot of people, it will bring to mind the next line "how I wonder what you're at", hence the mystery. It's not a title that Amazon can find as having been used for a contemporary novel, so you are less likely to be sued for using it. (Titles can't be copyrighted anyway, but that would not prevent some people from filing a lawsuit nor, necessarily, prevent a court from finding against you.)

Unless you're self-publishing, your publisher may well want you to change the title to something that meets their marketing criteria, so I advise you not to get too stuck on a particular title.

Clarification/Follow-up by denberg on 12/14/06 4:28 pm:
I guessed that, Jim! Actually it's for a friend of mine who wrote the book...I know the publisher will almost certainly reject it and impose one of his own but I have to try!

Detective...bats...murdered scientists and security guards in a lab...spacecraft...aliens...full moon...night settings...

Let me know if anything comes to mind!

Many thanks,

Paul.