Books often require an ISBN (International Standard Book Number). An ISBN number and a scannable bar code are separate items. Bookstores always require ISBN's, but if you’re planning on selling your book elsewhere it’s worth your while to determine whether the retailer will accept a UPC or EAN bar code instead. If you purchase an ISBN number and need it converted into a scannable bar code, Bar Codes Talk can do that for you. Contact Us! If your retailer will accept a UPC or EAN bar code, we can supply you with everything you need.