18.4 million. That's a hell lot of books.
Check them out: http://www.usabledatabases.com/database/books-isbn-covers/
And some sample records: http://www.usabledatabases.com/database/books-isbn-covers/sample/
Now for just $689.95, you can own a similar books database that could be powering Google Books and Amazon.
Each of the 18.4 million books have over 20 data fields about it. There are also 1 million book cover images in JPEG included in the download package. You can instantly deploy the database in your own project. If you know MySQL that would be a lot better.
This database is constantly being updated but we release an update every 12 or so months. Existing customers would be able to download the update when we release it.