It's simple! Your Books all have a barcode on the cover. Simply locate the barcode and type all of the numerical digits above or under the barcode into the search box, including any at the beginning or end of the sequence that may be smaller than the other characters. All you need to do here is type in the ISBN above or under the barcode. If your book does not have an ISBN on the back then it will be on the publishing details page at the front of your book. In most cases this will be a few pages in from the cover. If it does not have an ISBN at all, we cannot accept it.