The edition notice (or copyright page) is the page in a book containing information about the current edition, usually on the back of the title page. It often contains a copyright notice, legal notices, publication information, printing history, cataloguing information from a national library, and an ISBN that uniquely identifies the work. At the bottom of the edition notice one often finds a line of numbers, some of which may appear to be missing, called the printer's key. These indicate the book's print run.