ISBN

Every retailer, wholesaler, and library orders and lists your book by this number, and the title, contributors, format, price, and publication date attached to it are what those systems display, so one wrong detail shows up in many places at once. Traditionally and hybrid published authors normally receive the numbers from the publisher and check what is attached to each one. If you publish the book yourself, you buy the numbers and assign them, and you are the one who decides whether your imprint or a platform is recorded as the publisher. Keep one list of every ISBN beside the edition and format it identifies so you can check listings against it.

The International Standard Book Number identifies one specific edition and format of a book. A hardcover, a paperback, an ebook, and an audiobook are four products, so they normally carry four ISBNs.

Most editions and formats sold through the book trade need their own International Standard Book Number. Some platforms let you publish a platform-specific ebook or audiobook without buying one. If you assign an ISBN, use a different number for each separately available product format and edition that the ISBN rules treat as distinct.

There are two versions of the same number. ISBN-13 is the current standard: 13 digits, starting with 978 or 979. It is what every form and retailer asks for today. ISBN-10 is the older, 10-digit form of the same number, still printed on some older books and shown on Amazon beside the ISBN-13. One converts to the other, with one exception: a 979 number has no ISBN-10 form.

The ISBN is the key that retailers, wholesalers, distributors, and libraries use to order, list, and track a product. The title, contributors, format, price, and publication date attached to the ISBN in the publisher's metadata feed are what those systems display.

Record every ISBN your book has, and note which format each one belongs to. Then check what is attached to each number on the major retailer and library records. If something is wrong, the correction goes upstream to whoever controls the metadata feed, not to each retailer one at a time.

If you publish the book yourself in the United States, you buy ISBNs from Bowker. Do not use an ISBN supplied by a platform if you want to be listed as the publisher of record.

1. Ask your publisher for the ISBN of every planned edition and format.
2. Search each ISBN on Amazon, Bookshop.org, Google Books, and WorldCat.
3. Confirm the title, subtitle, contributors, format, page count, price, and publication date match on every listing.
4. Log any mismatch and the party who controls that record.

An ISBN is not required for everything. Some platforms will publish a platform-specific ebook or audiobook under their own identifier, so a book can sell without one. That is a real choice with a real cost: without an ISBN of your own, the edition is harder for retailers, wholesalers, and libraries outside that platform to order and track, and you are not the publisher of record.

An ISBN is not a copyright registration, a barcode, or a library catalog number. The barcode on the back cover encodes the ISBN, but the number exists independently of it. The LCCN and the OCLC number are different identifiers used by libraries.

ISBN-10 and ISBN-13 are not two different identifiers. They are the same identifier at two lengths, which is why Amazon and other retailers often show both on one product page. Converting between them finds the same book, except for a 979 number, which has no ISBN-10 form at all.