The U.S. ISBN Agency at Bowker, is the only official source of ISBNs in the United States and its territories. With an ISBN you can manufacture your publication and sell them anywhere in the world. The US ISBN Agency can only assign ISBNs to publishers located in the United States and its territories. Publishers located in other countries must obtain their ISBNs from their local ISBN Agency. The purpose of the ISBN is to establish and identify one title or one unique edition of a title from one specific publisher. An ISBN allows for more efficient marketing and cataloging of products by booksellers, libraries, universities, wholesalers, and distributors.
As part of its duty to the International ISBN Agency Bowker collects information about books published in the United States. Bowker also provides information and advice on the uses of the ISBN system to publishers, self-publishers, authors, and the book trade, and promotes the use of the Bookland EAN bar code format.