The books that are from Amazon already have the isbn numbers as part of their metadata. But I have a fair number of books from more... uh, dubious sources.

However, I see that Amazon is now putting a Book Description paragraph with each book they list, or at least with the half dozen that I just sampled. Their collection is over a million books now, so chances are that they will have many if not most of the books in my collection. As you (and RobotCaleb) suggested, Amazon may be what I'm looking for.

tanstaafl.