ISBN

The ISBN is a standardized identifier assigned to books, intended to simplify distribution, inventory management, and sales tracking across publishers, retailers, and libraries. Each edition or variation of a book (hardcover, paperback, audiobook) gets its own unique ISBN.

ISBN structure:

• 13 digits (formerly 10 digits pre-2007)
• Issued by national ISBN agencies
• Encodes country, publisher, title, and format

In the Amazon ecosystem:

• ISBNs are used to match or create listings in the Books category
• Required for publishing and selling via Kindle Direct Publishing (KDP)
• Help avoid duplication and listing errors in Amazon’s catalog
• Serve a similar role to GTINs/EANs but specific to books

💡 Example: A publisher releasing a hardcover and a paperback version of the same novel must assign two separate ISBNs to list them correctly on Amazon.

In short:
ISBN is a unique identifier for books, used by Amazon and the publishing industry to accurately manage, sell, and catalog titles across formats and marketplaces.