What is an International Standard Book Number (ISBN)?

The International Standard Book Number (ISBN) is a unique numeric identification code for published books. Affiliates of the International ISBN Agency sell ISBNs to publishers.

How does an ISBN Work?

Every edition and variation (except reprinting) of a book has an ISBN. The hardcover, paperback and e-book editions of a book will have different ISBNs. Before 2007, ISBNs had 10 digits but from 1 January 2007, ISBNs have 13 digits. 

Assigning an ISBN varies by country, but it largely depends on the scale of a nations publishing industry. 

The first ISBN code was created in 1967. It was based on the 9-digit Standard Book Numbering (SBN) of 1966. The International Organization for Standardization (ISO) created the 10-digit ISBN format. The ISO published the new format in 1970 with the code ISO 2108. 

To convert the SBN to ISBN, prefix the 9-digit code with zero (0). Occasionally, privately published books may lack an ISBN. However, the International ISBN Agency may decide to assign ISBNs to such books. The International Standard Serial Number (ISSN) is a unique identifier assigned to periodical publications including magazines, while musical works receive the International Standard Music Number (ISMN). 

 Except for reprinting, each edition and variation of a book has an ISBN. Thus, the hardcover, paperback, and e-book edition of a book have a different ISBN. Prior to 2017, ISBN has 10 digits, but ISBNs issued from January 1, 2017 have 13 digits. 10-digit ISBNs comprise 4 parts while 13-digit ISBNs have 5 parts. 

What are the Parts of an ISBN?

ISBN has the following parts:

• The prefix element (for 13-digit ISBN)
• Registration group
• Registrant
• Publication
• Check digit

A 13-digit ISBN has a prefix element. The registration group element represents the territory, individual country or language-sharing country group. The elements of an ISBN are separated with hyphens or spaces in 10-digit and 13-digit ISBN formats. Because the parts of an ISBN do not have the same number of digits, separating them correctly is often difficult. 

How ISBNs Are Issued? 

The ISBN registration agency for each country or territory issues ISBN for publications within its domain, irrespective of the publication language. Individual countries are assigned ranges of ISBNs according to the size of their publishing industry. Thus, the number of books, number, size and type of active publishers determines the ranges of ISBN assigned to each country. ISBN registration agencies may be government run or nongovernmental organizations such as bibliographic data providers. Registration Group Identifier The ISBN registration group identifier is 1 to 5 digits number valid within a single prefix element including 978 or 979 which can be separated using hyphens as in 978-1-. Registration group identifiers occupy the 978 prefix element. Within the 978 prefix element, the single-digit group identifiers include:

• 0 or 1 for English-speaking countries
• 2 for French-speaking countries
• 3 for German-speaking countries
• 4 for Japan
• 5 for Russian-speaking countries
• 7 for Peoples Republic of China

For example, Bhutan uses 99836 as its 5-digit group identifier. Allocated group IDs include:

• 05
• 600622
• 65
• 7
• 8094
• 950989
• 99209989, and
• 9990199981

Typically, books published in rare languages are assigned longer group identifiers. The ISBN reserves the registration group identifier 0 within the 979 prefix element as an alternative to the International Standard Music Numbers (ISMNs). However, the ISBN is not assigned to such works. Within the prefix element 979, France, the Republic of Korea and Italy have been assigned 10, 11, and 12 registration group identifiers, respectively. There was no registration group identifier in the 9-digit SBN, but it can become a valid 10-digit ISBN by prefixing with a zero (0). 

What is the Registrant Element?

The ISBN agency for a country issues the registrant element and a range of ISBNs within that registrant element to a publisher. The publisher assigns each of its books one of the ISBNs. While most countries do not mandate publishers to assign an ISBN, most bookstores only accept publications with ISBNs. The International ISBN Agency has over 900,000 assigned publisher codes available for purchase in book form for 1399 or US$1959. Publisher codes are accessible on the ISBN agencys site for a fee. However, incomplete lists of the English language catalogs covering identifier 0 and identifier 1 are available online. 

The number of ISBN blocks publishers receive depends on their size. A small publisher may receive a single digit for the publication element, several digits for the registrant element, and one or more digits for the registration group identifier. The publisher will receive another block of ISBN after exhausting the one at hand. Larger publishers may have more than one registrant elements or registration group identifier if all the registration elements in that group have been assigned. ISBN registration agencies use variable block lengths to customize each publishers ISBN allocations. For example, the agency may give a large publisher a block of ISBNs with fewer digits allocated for the registrant elements and multiple digits of publication elements. Also, countries with several publication titles allocate fewer digits for the registration group identifier while the publication and registrant elements get several allocations.