Can't find book via ISBN search, but can't add it because it already exists

[slm]

I did a search for Insider's Baseball both by title and ISBN (684179059) and couldn't find anything. So I tried to add the book and was told that there was already a book with that ISBN already in the database. So I double checked the number and retried the search but I still can't find the book.

What's causing this?

[Plethora]

Your ISBN is missing a 0 -- Insider's Baseball: The Finer Points of the Game, as Examined by the Society for American Baseball Research

[slm]

Well that's annoying. The ISBN printed on the back of the book is missing the zero.

Thanks.