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Bowker United States

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1) Your most important identifier
2) The global standard for books
3) Required by most retailers

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The most important identifier your book can have is the ISBN. As the U.S. ISBN Agency, Bowker is the ONLY official source of ISBNs in the United States. ISBNs provide unique identification for books and simplify the distribution of your books throughout the global supply chain. Without an ISBN, your book will not be found in most bookstores, either online, or down the street from your house.

Important Notice: Changes to ISBN Prefixes

The United States ISBN Agency will soon begin assigning ISBNs starting with the prefix element 979 (in addition to the ISBNs with prefix element 978 we currently assign). This is necessary because the inventory of certain ISBN block sizes starting with 978, such as 10,000, 100,000 and 1,000,000, are dwindling.

What does this mean for publishers, libraries and retailers?


Tools for getting discovered

The top three important tools for discovery are the ISBN, Barcode and Marketing your book. The 13 digit ISBN links to essential information used in sales tracking, retail inventory systems, library catalogs, bookstores, online stores, and for new digital editions for old books.

Complete, accurate identification

The purpose of the ISBN is to identify one specific version of a book. If you wish to have a print (hardbound or softbound) or electronic (ePUB,  PDF, or MOBI) version, or even register a new version, you will need a unique ISBN for each format. This allows retailers to help the customer understand exactly which version of a title they are purchasing.

Bibliographic immortality

A book can be found by its ISBN and the title data connected with it, long after the publisher has ceased to sell the book itself.

Link to essential Information

You may ask - why do I need an ISBN? An ISBN is essential for linking information which allows booksellers and readers to know: what your book is about, who the author is, and who the publisher is. Along with the barcode, it is crucial for tracking sales and inventory.


Bowker offers best-in-class customer service and technical support so you can hit the ground running with your Bowker products and leverage everything they can do.

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Bowker Barcode


A barcode is a graphical representation of your book's ISBN and in the United States, the price information. A ISBN is the most widely used format for identifying your book in the publishing industry.

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Thorpe Bowker Australia


The most important identifier your book can have is an ISBN (International Standard Book Number). Thorpe-Bowker is the ONLY official ISBN Agency for Australia.

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