The International Standard Book Number
The International Standard Book Number (ISBN) is a 10-digit number that uniquely identifies books and book-like products published internationally.
The purpose of the ISBN is to establish and identify one title or edition of a title from one specific publisher and is unique to that edition, allowing for more efficient marketing of products by booksellers, libraries, universities, wholesalers and distributors.
Every ISBN consists of ten digits and whenever it is printed it is preceded by the letters ISBN. The ten-digit number is divided into four parts of variable length, each part separated by a hyphen.
There are over 160 ISBN Agencies worldwide, and each ISBN Agency is appointed as the exclusive agent responsible for assigning ISBNs to publishers residing in their country or geographic territory. The United States ISBN Agency is the only source authorized to assign ISBNs to publishers supplying an address in the United States, U.S. Virgin Islands, Guam and Puerto Rico and its database establishes the publisher of record associated with each prefix.