The International Standard Book Number (ISBN) is a unique numeric commercial book identifier. For example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN.
The ISBN is10 digits long if assigned before 2007 and 13 digits long if assigned on or after 1 January 2007.
A 13-digit ISBN can be separated into: prefix element, registration group, registrant, publication and check digit.
The parts of a 10-digit ISBN and the corresponding EAN‑13 and barcode. Note the different check digits in each. The part of the EAN‑13 labeled "EAN" is the Bookland country code.