Navigating the World of ISBN: A Guide for Self-Publishing Authors

ISBN barcode on a book

For self-publishing authors, one of the most important steps in the publishing journey involves understanding the International Standard Book Number (ISBN). This globally recognized identification system plays a crucial role in the publishing industry and is something every author should become familiar with.

Understanding ISBNs

An International Standard Book Number, or ISBN, is a unique numeric identifier used globally for books. Established to provide a standardized system for the identification of each book variant, the ISBN is essentially a product code for books.

An ISBN has consisted of 13 digits since 2007; before then, it was a 10-digit number (ISBN-10). This expansion of the ISBN system was necessary to cope with the high volume of books being published worldwide. ISBN-10s assigned before the switch remain valid identifiers, but all new ISBNs assigned today are ISBN-13.

The Importance of ISBNs

ISBNs aren’t just a string of numbers on the back of a book; they play a significant role in the publishing industry. ISBNs enable efficient marketing of books by booksellers, libraries, universities, wholesalers, and distributors. With an ISBN, your book is entered into a global database, making it discoverable to anyone, anywhere in the world.

Having an ISBN allows your book to become part of the worldwide catalog of published material, enabling individual buyers, libraries, and large-scale suppliers to locate your book amidst millions of other titles. In essence, an ISBN opens the door to the global book market.

The Structure of an ISBN

ISBN barcode example

An ISBN-13 is made up of five parts:

  1. Prefix: This is always 978 or 979.
  2. Registration group element: This refers to the specific language-sharing country or geographical area.
  3. Registrant element: This identifies the particular publisher.
  4. Publication element: This signifies the particular edition and format of the publication.
  5. Check digit: A single digit at the end of the ISBN, which validates the ISBN.

Obtaining an ISBN

Application procedures for ISBNs vary by country, but they generally involve filling out a form and paying a fee. In the United States, the official ISBN agency is Bowker. On their website, you can apply for an ISBN by creating an account and following the step-by-step process.

Remember, each different format of your book, along with any new editions, requires its own unique ISBN. While some online publishing platforms offer a free ISBN when you publish through them, using these free ISBNs often results in the platform becoming the publisher of record. This could limit your book’s distribution potential and your control over it. To maintain the highest level of control over your book, purchasing your own ISBN is generally advised.

After securing your ISBN, the next step is to prepare your book for printing. Our article, Book Printing 101: A Beginner’s Guide to Printing Your First Book, provides a comprehensive guide to help you navigate this process smoothly.

ISBNs and Barcodes

For physical books, an ISBN is often incorporated into a barcode on the book’s back cover. This barcode enables retailers to scan your book directly into their sales systems, easing the process of stocking and selling your book. In addition to the ISBN, the barcode may also include the price of the book.

ISBNs and Ebooks

The requirement of an ISBN for ebooks is a bit more complex. Some ebook platforms and retailers require one, while others don’t. However, to ensure the broadest possible availability of your ebook across all platforms, assigning an ISBN to your digital book is often a good idea.

The Role of ISBN in Marketing and Distribution

Every book retailer, both physical stores and online platforms, relies on the ISBN system. When a book is published with an ISBN, that number is uploaded to global and national databases, which retailers, libraries, and distributors access to order new titles. Without an ISBN, your book would be virtually invisible to these institutions.

Furthermore, most booksellers’ systems are set up to read ISBN barcodes. This means your book can be easily scanned, tracked, and sold, which is beneficial not just for the booksellers but also for you in keeping track of your book’s sales.

Reprints, New Editions, and Different Formats

If your book is reprinted without any changes, you do not need a new ISBN. However, if there are significant changes such as a revised edition or translation, you must get a new ISBN for that edition. Also, every different format (hardcover, paperback, PDF, ePub, audiobook, etc.) of your book must have its own ISBN. The same applies to bundled books – if you sell a bundle of two different books, that bundle needs its own ISBN separate from the individual ones.


Understanding the world of ISBNs can seem daunting at first, but it’s a crucial part of the self-publishing process. When used correctly, ISBNs facilitate the distribution and marketing of your book, ensuring it reaches the widest possible audience.

Remember, it’s about more than just getting a number. It’s about making your work discoverable and giving it the recognition it deserves. Keep in mind that the purpose of an ISBN is to help, not hinder, your publishing journey.

For more in-depth information on ISBNs, check out the official ISBN Users’ Manual provided by the International ISBN Agency. This comprehensive guide will give you a clearer understanding of ISBNs and how they fit into your self-publishing strategy.