Book Knowledge Part 1: ISBN – Decoding the book numbers

By: Linnéa Jönsson

In this series, Digiteket explores the fascinating world of books and their history. This time, we’re unraveling the mystery of the International Standard Book Number (ISBN) – a system used daily in the book industry and libraries worldwide, yet whose origins remain obscure to many. We’ll decode the meaning behind each digit and delve into the system’s evolution.

Introduction

To the average person, the number 978 might seem insignificant. However, for those in the book industry, these digits are instantly recognizable as the opening sequence of most ISBNs. Whether you’re hunting for a specific edition or navigating through books with common titles, the ISBN is an indispensable tool. But what story do these numbers tell? How does ISBN-13 differ from its predecessor, ISBN-10? And why don’t 70-year-old books have an ISBN?

Purpose

This course explains what the ISBN system is and what the different parts of the numbers mean and their function. The course also provides a brief historical overview of how and why the ISBN system was created and how it has changed and developed over time.

Course Objectives 

When you’ve completed this course, you’ll be able to:

• Define ISBN and recount its historical development
• Interpret the different segments of an ISBN
• Understand the process of ISBN assignment
• Identify which media formats are eligible for ISBN assignment

A Note on Terminology

In Swedish, you might hear people say ”ISBN number,” which is technically redundant (like saying ”PIN number”). Throughout this course, we’ll simply use ”ISBN,” following the convention set by the National Library of Sweden (Kungliga biblioteket).

Acknowledgments

I extend my gratitude to Carina Bäck Ekberg and Ingvar Persson from ISBN Sweden for their assistance and fact-checking during the development of this course. I would also like to thank Nick Woods from the International ISBN Agency for permission to use the image of David Whitaker.

Decoding ISBN

ISBN is an acronym that stands for International Standard Book Number and is a standard for identifying media, or ”a unique identifier for monographic publications, such as books and maps, that are published for general distribution” as the National Library of Sweden describes it (in library science, the term monograph is often used to mean a separately published work, as opposed to periodical literature such as journals). It might seem natural that all books have a number so they can be easily found, identified, and cataloged. But in fact, ISBN’s history is younger than one might think.

Ten or Thirteen? 

In the early 2000s, the ISBN system faced a critical challenge: it was running out of numbers. The original 10-digit system theoretically allowed for a billion unique combinations. However, due to its hierarchical structure (which we’ll explore later), the actual capacity was much lower. The rapid expansion of digital publishing formats and the proliferation of new publishing houses dramatically increased the demand for ISBNs. To ensure the standard would be viable for a long time into the future, the International ISBN Agency decided to increase the number of digits, and since 2007, all ISBNs are thirteen digits long.

History

A Bookseller and a Statistician 

The ISBN standard actually doesn’t have its origins in the library world but in the 1960s bookselling industry.  In 1965, the British bookstore chain WHSmith embarked on an ambitious project: building a vast, computer-controlled book warehouse. To streamline their inventory management, they needed a standardized numbering system for all their books. To do this, they hired Gordon Foster, a professor of statistics at the London School of Economics (LSE). He developed a 9-digit code system that he named the Standard Book Numbering System (SBN). But the person who spread and popularized this standard was British publisher David Whitaker. Whitaker, who is often referred to as ”the father of ISBN,” understood the importance of all publishers using a common system to better organize the books they published and sold.

In an interview, he painted a vivid picture of the pre-SBN era: ”Say, for example, that you were looking for a particular edition of Black Beauty. Previously, you had to go through 125 alpha-numeric characters before you could identify the unique edition that you wanted.”

Whitaker, through his family business J. Whitaker & Sons, took on the monumental task of assigning SBN numbers to all newly published books in the UK. He made it his mission to integrate the SBN into every aspect of book publishing, from bibliographic descriptions to publishers’ catalogs. He eventually managed, despite some resistance from certain publishers, to convince more and more publishing companies in the UK to start using the system. Together with a colleague, he printed an SBN manual which he distributed free of charge to all British publishers. J. Whitaker & Sons, the publishing house his father had founded, also published the magazine The Bookseller, an influential voice in the UK publishing industry at that time. This ensured that news of the new SBN system spread rapidly throughout the British publishing world. By the end of 1967, all newly published British books were being assigned SBN numbers.

From National to International: The Birth of ISBN

The next important step in the story of ISBN was to develop the standard for an international market. The system became successful and soon spread to several English-speaking countries such as Australia, New Zealand, South Africa, and the USA. There was also interest from German publishers, and in 1968, representatives from countries including the USA, Germany, the Netherlands, Ireland, and the Scandinavian countries gathered in Berlin to discuss how to develop a book standard that could be implemented worldwide. The International Organization for Standardization (ISO) was also involved, which is the organization that has developed standards for everything from paper formats to units of measurement. Whitaker managed to convince ISO that an international standard for books was needed, and in 1970, ISO 2108, an international standard for books, was published. This marked the transition from SBN to ISBN. To maintain and evolve the standard, Whitaker established the International ISBN Agency. Each participating country set up its own ISBN agency to manage number allocation. In Sweden, this role is fulfilled by ISBN Sweden, a division of the National Library of Sweden. 

When asked about the rapid global adoption of the system in an interview, Whitaker attributed it to the spirit of the times: “It was an idea whose time had come. It was also the swinging sixties, a time when anything was possible, even cooperation between publishers!” 

Decoding the ISBN

As mentioned earlier, all ISBNs are divided into different blocks that designate different things, these different blocks are often separated by hyphens, such as 978-91-8719-326-2. These numbers are often separated by hyphens for readability, but you might also see them without separators. ISBN is often written without hyphens in many contexts, and it’s often perfectly fine to search for ISBN in databases without hyphens. For example when searching in databases like Libris (the Swedish national library database), you’ll need to omit the hyphens. In printed books, however, the different blocks should, according to the ISBN Agency, be clearly separated with either hyphens or spaces. 

An ISBN consists of five distinct parts:

1. Prefix element
2. Group element
3. Registrant element (publisher)
4. Title element
5. Check digit

1. The first part, the prefix, in this case 978, is the newest part of the ISBN that was added when the standard became thirteen digits. This number tells what the object is, in this case a book. This part of the ISBN almost always consists of the numbers 978. However, it’s good to know that 979 can also occur and may become more common in the future. These two prefixes have exactly the same meaning, that it’s a book. This has to do with the International ISBN Agency wanting to guarantee the longevity of the current standard even more by already having two different number combinations. Currently, 978 is still the most common. The prefix is always three digits long.
   
   
2. The second part, 91, is called the group element, and it’s an area designation code that represents a national, geographical or language area. For instance, 91 is Sweden’s country code. English-language publications often use 0 or 1 and a book that has 0 or 1 as its group designation could thus be published in Canada, the UK, the USA, or any other English-speaking country, it’s not possible to know in which country the book is published. The field can consist of anything from one to five digits, but the entire ISBN is always ten or thirteen digits long. If you’re more interested in area designations, there’s a list of all current ISBN area designations on Wikipedia.
   
   
3. The third block, 8719, is a registrant or publisher designation that tells which publisher the book is published by. However, it’s good to know that even though the publisher designation numbers are unique within each area (for example, nation or language area), they are not unique internationally. 8719 can thus designate one publisher in Sweden and a completely different one in Finland. The publisher designation can be up to seven digits long. A publisher doesn’t necessarily have to be a publishing house (although it’s the most common) but can be, for example, a private individual, association, company, or organization.
   
   
4. Block number four, 326, is a title designation that identifies a specific edition and format for a specific title. This can be up to 6 digits long.
   
   
5. The last field is a so-called check digit that validates the entire number, it’s always only one digit between zero to nine. This digit is the one that mathematically validates the rest of the number. The check digit is the ISBN part that is hardest to evaluate because it’s based on modular arithmetic, a certain area of mathematics. The validation of the number itself thus occurs by inserting all the digits into a mathematical formula, something that requires higher mathematical knowledge than most people have. But for those who are curious, Wikipedia explains how to calculate ISBN-10 and ISBN-13 respectively, using check digits. In the original ISBN-10, the Roman numeral X was always used. Since ISBN-13 was introduced in 2007, the use of the number ten/X was discontinued because it wasn’t compatible with the EAN barcode standard.

If we start from the previously mentioned example (978-91-8719-326-2), we now know that it’s a book and that it’s published in Sweden. However, we don’t know if the book is in Swedish or any other language, only that it’s published in Sweden. If a Swedish publisher, for example, wants to publish an English textbook in Sweden, the book gets the area designation 91, not 0 or 1. Which publisher the book is published by is difficult to find out just by looking at the ISBN because there’s no publicly available list of Swedish publishers and their publisher designations. However, there’s the Swedish ISBN register, which is the entire ISBN Sweden database in searchable form, but it’s not a directory per se. However, you can search for a publisher designation in the register and see which publisher it belongs to.

When we search for the complete ISBN (9789187193262) in, for example, Libris, we find out that the book is called Frankenstein eller den moderne Prometheus, is written by Mary Shelley, translated by Monica Stolpe, and published in Sweden in 2017 by Sjösala förlag. If we look up another title published by the same publisher, for example Dracula, written by Bram Stoker, we can see that it has ISBN 978-91-8719-347-7. We can then conclude that 8719 is Sjösala förlag’s publisher designation. If we try the same thing with Jan Guillou’s Brobyggarna (978-91-6420-319-9) and Emma Ångström’s Det hon begraver (978-91-6420-881-1), both published by Piratförlaget, we see that 6420 is Piratförlaget’s publisher designation. We can also search for 6420 in the aforementioned Swedish ISBN register to find out which publisher published each book.

ISBN in practice 

It’s important to remember that each separate edition of a publication is assigned its own ISBN. However, a reprint of a specific title doesn’t mean that the book gets a new ISBN. In practice, this means that the same title can have completely different covers but still have exactly the same ISBN. An e-book, a paperback, and a hardcover edition of the same title always have different ISBNs. For example, while an unchanged reprint of, say, the hardcover edition of a specific book can have the same ISBN but a completely different cover. However, if the book is published in a new edition, a new ISBN is required. In case of only a cover change, the publisher can choose to assign a new ISBN or keep the same ISBN.

When a book, for example, has been assigned an ISBN, the unique number can never be used again. However, it has happened that different books have mistakenly been given the same ISBN because the publisher in question didn’t double-check that an ISBN didn’t already exist. For example, the two books Ninja Gaiden, published in 1990, and Wacky laws, published in 1997, both have the following ISBN: 0-590-76484-5.

Assignment of ISBN 

As mentioned earlier, each country has its own unit where book publishers can apply for ISBN. In some countries, the use of ISBN to identify publications has been made a legal requirement, but not in Sweden. According to ISBN Sweden, it’s not mandatory to get an ISBN for the books you publish, but it facilitates the handling of publications both within the book industry and in libraries. Some booksellers even have a principle of not buying books that lack ISBN. Usually, it’s the publisher and not the author(s) who handle the application for ISBN, and it’s done by applying on the National Library of Sweden’s website. It’s free of charge and it takes about 10 working days to get an ISBN. The only requirement is that the publisher of the book has a Swedish address that must be provided when applying.

Not Only Books 

Although ISBN was originally used for books, it’s now used for other media formats as well. According to the National Library of Sweden’s information about ISBN, the following are examples of publications that can be assigned ISBN:

• Printed books and brochures
• Braille publications
• Maps
• Educational or instructional films
• Audiobooks and e-books
• Digitized copies of printed monographs

According to the National Library, the following are examples of publications that should not be assigned ISBN:

• Sheet music/scores
• Music recordings
• Continuing resources such as newspapers, magazines, and yearbooks (these should instead be assigned ISSN, another system)
• Games
• Art prints and art portfolios without title page and text
• Individual companies’ catalogs, price lists, user manuals
• Theater and exhibition programs
• Almanacs and calendars
• Forms
• Personal documents such as CVs or personal profiles

Summary

Now you have hopefully learned a bit more about how ISBN works and the history behind the system’s creation. Hopefully, you have also become even more convinced of how smart and practical this system is for anyone looking for books. If you want to delve deeper into the subject, The International ISBN Agency has a lot of information on its website. The National Library of Sweden and ISBN Sweden also have some information about ISBN on their website. They also have a FAQ page about ISBN, which is primarily aimed at authors and book publishers. Now that you have gained basic knowledge on the subject, try searching for specific ISBNs on Google or in Libris and see what happens!