If you want your published book to be available for sale to the general public, then you’re probably already aware of ISBNs. Possibly you’ve looked at the back of a printed book, seen a series of 13 numbers listed on a barcode, and wondered what they have to do with the actual content of the book. For the reader, this barcode probably seems like just another random publication detail. However, as an author, the ISBN and barcode are significant for you.

What is an ISBN and why do you need it for your book?

First up, ISBN is an acronym for ‘international standard book number’. It is a globally recognised 13-digit marker within the publishing industry that identifies a specific book title. An ISBN provides a record of a book’s metadata (including the publisher, the title and the country it was published in) and is unique to that book. ISBNs are used by publishers, booksellers, libraries and online book retailers for ordering, listing, sales records and stock control purposes.

There are millions of books available for sale, so it is easier to identify a specific book by its ISBN rather than by title or author name. By purchasing an ISBN or a bulk block of 10 ISBNs (or more), you are then recorded as being the official publisher of your book. ISBNs are sold by national agencies within each country. In the USA, Bowker deals with ISBN sales, and in the UK, it is Nielsen. In Australia, the organisation responsible for issuing ISBNs is Thorpe-Bowker, and you can purchase either a single ISBN or a bulk order of 10 ISBNs directly from their website.

Composition of ISBNs

The numbers that make up an ISBN are grouped into five different sections. The first three numbers are known as the ‘prefix element’, and they are either 978 or 979. The next (single-digit) number is the ‘registration group element’, which indicates the book’s country or language group. The third aspect is the ‘registrant element’, which is used to identify the publisher. Following on is the ‘publication element’, which identifies the format or edition of the book title. And finally, the ‘check digit’ is used to validate all the associated elements in the ISBN.

Every format of your book requires a new ISBN

Each version of a published book title (e.g. paperback, hardcover, ebook or audiobook) requires a separate ISBN. For this reason, every time you want to publish a new format of your book, you will need to use a new ISBN. The reason for this is that ISBNs can’t be reassigned or transferred. Likewise, if you translate an existing book into a new language, it requires a new ISBN. A change to the book title, as well as any major revisions or updates to the internal content, are other reasons your book would need a new ISBN. So you can see that purchasing a block of 10 ISBNs up front is a good idea.

What is the difference between an ISBN and a barcode?

An ISBN and the barcode on the back cover are essentially the same thing: data that identifies your book. The major difference between them is how the data is presented. An ISBN is a sequence of numbers separated by spaces or hyphens. On the other hand, a barcode is the same sequence represented as a series of vertical lines. If you look at the numbers next to the lines in the barcode, you will observe they are exactly the same digits, occurring in the same sequence, as the ISBN. However, they serve different purposes. On its own, an ISBN is readable by humans, but if you want to include those details in a publishing database, you need to convert it into a computer-generated barcode. In other words, the barcode is the machine-readable format of an ISBN.

ISBN barcodes are mostly used by distributors and retailers to keep a record of book titles they currently have in stock. By scanning the ISBN barcode, they are able to track the complete inventory information for a specific book title. Every printed version of a book available for sale requires an ISBN barcode, which is positioned in the lower right-hand corner (or sometimes the middle) of the back cover.