In-depth articles on ISBNs, publishing, and the international book number system — written for authors, publishers, and curious readers.
The barcode on every book cover encodes the ISBN-13 using the EAN-13 standard. We explain how the barcode system works, what the price add-on means, and how to generate a correct barcode for your book.
Every ISBN contains a publisher prefix that identifies who issued the book. We explain how publisher prefixes are assigned, what their length tells you, and how to use publisher prefix pages to research any imprint.
Audiobooks are a distinct product that require their own ISBNs. We cover when audiobook ISBNs are required, how ACX and other platforms handle them, and best practices for multi-format publishing.
In the United Kingdom, Nielsen Book is the official ISBN agency. This guide covers how to register for ISBNs through Nielsen, what the UK registration process involves, and how it differs from Bowker in the US.
Bowker is the sole official ISBN agency in the United States. This guide explains how to purchase ISBNs through myidentifiers.com, register your metadata, and set up your publisher account correctly.
Ebooks and print books have different ISBN requirements across different platforms. We clarify what's mandatory, what's optional, and how to handle multi-format publishing correctly.
The check digit is the last character of any ISBN, and it's calculated from all the other digits. Understanding it reveals an elegant piece of error-detection mathematics built into every book.
Reading an ISBN goes beyond recognizing it as a number. Each of its five segments tells you something specific about a book's origin and publisher. Here's how to decode every part.
The registration group element of an ISBN identifies a country, language area, or territory. We explain how groups are assigned, what the numbers mean, and how to look up any group.
Getting an ISBN as an independent author can be confusing. We break down where to buy ISBNs, how many you need, free vs. paid options, and what it means for your publisher of record.
The book industry switched from 10-digit to 13-digit ISBNs in 2007. We explain the differences, how to convert between formats, and when each version still matters today.
Every published book carries a unique numeric fingerprint called an ISBN. Learn how this 13-digit standard was designed, what each segment means, and why the system matters for authors, publishers, and readers worldwide.