Information taken from The New York Public Library Writer’s Guide to Style and Usage, HarperCollins Publishers, 1994.
On the copyright page, which is the verso of the title page of every book, among much other information you can find the ISBN (International Standard Book Number). The ISBN is a ten-digit number unique to each book. It is a code that tells where the book was published, identifies the publisher and includes other numbers that differentiate the book’s ISBN from all others.
When there are different editions of the same book (for example, hardcover and paperback), each edition must have its own ISBN. Multivolume sets have several ISBNs – the set itself has one and each volume within the set has its own. Serial publications such as monographs or journals carry International Standard Serial Numbers (ISSNs). The ISSN is an eight-digit number that stays the same for each issue of the series.
The ISBN numbering agency for U.S. publishers is operated by the R. R. Bowker Company. When a publisher registers with this agency, it is given a four-digit identification number that becomes part of the ISBN for all of its publications. The number must be assigned in the earliest stages of the publishing process to become part of the Library of Congress Cataloging in Publication (CIP) data that libraries and booksellers use as an aid to cataloging. The agency will issue a publisher a series of ISBN numbers that can be assigned to future books. The publisher then notifies the agency as the numbers are used, rather than repeating the application process each time.
The ISBN also appears as part of the barcode, or Universal Product Code, placed on the bottom of a book’s back cover. The other numbers in the barcode represent the Bookland EAN, an international numbering scheme for the book trade. The digits 978 form the prefix to this number and are followed by the book’s ISBN. An additional five-digit code can be used to show price and currency. These barcodes speed the purchasing and inventory process for wholesalers and booksellers.
For more information, contact the International Standard Book Numbering Agency, R.R. Bowker, 121 Chanlon Road, New Providence, N J 07974, (908) 665-6770).