ISBN
Also called International Standard Book Number
The thirteen-digit number that identifies one edition of a book, issued to the publisher by the national ISBN agency. A paperback and a hardback of the same title each have their own.
In practice
The ISBN is the publisher’s business; what the printer needs from it is the barcode. Supply the EAN-13 artwork ready to place on the back cover, or the number so the barcode can be generated, and check on the proof that it prints black on a pale ground with no flap, die-cut or varnish over it.