The International Standard Book Number (ISBN) is a unique numeric commercial book identifier.

An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, and 10 digits long if assigned before 2007. The method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country.

The initial ISBN configuration of recognition[clarification needed] was generated in 1967 based upon the 9-digit Standard Book Numbering (SBN) created in 1966. The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108 (the SBN code can be converted to a ten digit ISBN by prefixing it with a zero).

A book can be printed without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure; however, this can be rectified later.

Another identifier, the International Standard Serial Number (ISSN), identifies periodical publications such as magazines; and the International Standard Music Number (ISMN) covers for musical scores.

History
The Standard Book Numbering (SBN) code is a 9-digit commercial book identifier system created by Gordon Foster, Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers WHSmith and others in 1965. The ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker (regarded as the "Father of the ISBN"[5]) and in 1968 in the US by Emery Koltay (who later became director of the U.S. ISBN agency R.R. Bowker).

The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108.[3][4] The United Kingdom continued to use the 9-digit SBN code until 1974. ISO has appointed the International ISBN Agency as the registration authority for ISBN worldwide and the ISBN Standard is developed under the control of ISO Technical Committee 46/Subcommittee 9 TC 46/SC 9. The ISO on-line facility only refers back to 1978.

An SBN may be converted to an ISBN by prefixing the digit "0". For example, the second edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has "SBN 340 01381 8" – 340 indicating the publisher, 01381 their serial number, and 8 being the check digit. This can be converted to ISBN 0-340-01381-8; the check digit does not need to be re-calculated.

Since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with "Bookland" European Article Number EAN-13s

Overview
An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, and 10 digits long if assigned before 2007. An International Standard Book Number consists of 4 parts (if it is a 10 digit ISBN) or 5 parts (for a 13 digit ISBN):
The parts of a 10-digit ISBN and the corresponding EAN?13 and barcode. Note the different check digits in each. The part of the EAN?13 labeled "EAN" is the Bookland country code.

for a 13-digit ISBN, a prefix element – a GS1 prefix: so far 978 or 979 have been made available by GS1, the registration group element (language-sharing country group, individual country or territory), the registrant element, the publication element,and a checksum character or check digit.

A 13-digit ISBN can be separated into its parts (prefix element, registration group, registrant, publication and check digit), and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts (registration group, registrant, publication and check digit) of a 10-digit ISBN is also done with either hyphens or spaces. Figuring out how to correctly separate a given ISBN is complicated, because most of the parts do not use a fixed number of digits.

How ISBNs are issued
ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for that country or territory regardless of the publication language. The ranges of ISBNs assigned to any particular country are based on the publishing profile of the country concerned, and so the ranges will vary depending on the number of books and the number, type, and size of publishers that are active. Some ISBN registration agencies are based in national libraries or within ministries of culture and thus may receive direct funding from government to support their services. In other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the stated purpose of encouraging Canadian culture. In the United Kingdom, United States, and some other countries, where the service is provided by non-government-funded organisations, the issuing of ISBNs requires payment of a fee.

Australia: ISBNs are issued by the commercial library services agency Thorpe-Bowker, and prices range from £65 for a single ISBN (plus a $55 registration fee for new publishers) to £2,890 for a block of 1,000 ISBNs. Access is immediate when requested via their website.

Brazil: National Library of Brazil, a government agency, is responsible for issuing ISBNs, and there is a cost of R$16

Canada: Library and Archives Canada, a government agency, is responsible for issuing ISBNs, and there is no cost. Works in French are issued an ISBN by the Bibliothèque et Archives nationales du Québec.

Colombia: Cámara Colombiana del Libro, a NGO, is responsible for issuing ISBNs. Cost of issuing an ISBN is about USD$20.

Hong Kong: The Books Registration Office (BRO), under the Hong Kong Public Libraries, issues ISBNs in Hong Kong. There is no fee.

India: The Raja Rammohun Roy National Agency for ISBN (Book Promotion and Copyright Division), under Department of Higher Education, a constituent of the Ministry of Human Resource Development, is responsible for registration of Indian publishers, authors, universities, institutions, and government departments that are responsible for publishing books.[19] There is no fee associated in getting ISBN in India.

Italy: The privately held company EDISER srl, owned by Associazione Italiana Editori (Italian Publishers Association) is responsible for issuing ISBNs. The original national prefix 978-88 is reserved for publishing companies, starting at €49 for a ten-codes block while a new prefix 979-12 is dedicated to self-publishing authors, at a fixed price of €25 for a single code.

Maldives: The National Bureau of Classification (NBC) is responsible for ISBN registrations for publishers who are publishing in the Maldives.

Malta: The National Book Council (Maltese: Il-Kunsill Nazzjonali tal-Ktieb) issues ISBN registrations in Malta.

Morocco: The National Library of Morocco is responsible for ISBN registrations for publishing in Morocco and Moroccan-occupied portion of Western Sahara.

New Zealand: The National Library of New Zealand is responsible for ISBN registrations for publishers who are publishing in New Zealand.

Pakistan: The National Library of Pakistan is responsible for ISBN registrations for Pakistani publishers, authors, universities, institutions, and government departments that are responsible for publishing books.

Philippines: The National Library of the Philippines is responsible for ISBN registrations for Philippine publishers, authors, universities, institutions, and government departments that are responsible for publishing books. As of 2017, a fee of ?120.00 per title was charged for the issuance of an ISBN.

South Africa: The National Library of South Africa is responsible for ISBN issuance for South African publishing institutions and authors.

United Kingdom and Republic of Ireland: The privately held company Nielsen Book Services Ltd, part of Nielsen Holdings N.V., is responsible for issuing ISBNs in blocks of 10, 100 or 1000. Prices start from £120 (plus VAT) for the smallest block on a standard turnaround of ten days.

United States: In the United States, the privately held company R.R. Bowker issues ISBNs.[4] There is a charge that varies depending upon the number of ISBNs purchased, with prices starting at $125 for a single number. Access is immediate when requested via their website.

Publishers and authors in other countries obtain ISBNs from their respective national ISBN registration agency. A directory of ISBN agencies is available on the International ISBN Agency website.
Registration group identifier

The registration group identifier is a 1- to 5-digit number that is valid within a single prefix element (i.e. one of 978 or 979). Registration group identifiers have primarily been allocated within the 978 prefix element. The single-digit group identifiers within the 978 prefix element are: 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; and 7 for People's Republic of China. An example 5-digit group identifier is 99936, for Bhutan. The allocated group IDs are: 0–5, 600–621, 7, 80–94, 950–989, 9926–9989, and 99901–99976. Books published in rare languages typically have longer group identifiers.

Within the 979 prefix element, the registration group identifier 0 is reserved for compatibility with International Standard Music Numbers (ISMNs), but such material is not actually assigned an ISBN. The registration group identifiers within prefix element 979 that have been assigned are 10 for France, 11 for the Republic of Korea, and 12 for Italy.

The original 9-digit standard book number (SBN) had no registration group identifier, but prefixing a zero (0) to a 9-digit SBN creates a valid 10-digit ISBN.
Registrant element

The national ISBN agency assigns the registrant element (cf. Category:ISBN agencies) and an accompanying series of ISBNs within that registrant element to the publisher; the publisher then allocates one of the ISBNs to each of its books. In most countries, a book publisher is not required by law to assign an ISBN; however, most bookstores only handle ISBN bearing publications.[citation needed]

A listing of more than 900,000 assigned publisher codes is published, and can be ordered in book form (€1399, US$1959). The web site of the ISBN agency does not offer any free method of looking up publisher codes. Partial lists have been compiled (from library catalogs) for the English-language groups: identifier 0 and identifier 1.

Publishers receive blocks of ISBNs, with larger blocks allotted to publishers expecting to need them; a small publisher may receive ISBNs of one or more digits for the registration group identifier, several digits for the registrant, and a single digit for the publication element. Once that block of ISBNs is used, the publisher may receive another block of ISBNs, with a different registrant element. Consequently, a publisher may have different allotted registrant elements. There also may be more than one registration group identifier used in a country. This might occur once all the registrant elements from a particular registration group have been allocated to publishers.

By using variable block lengths, registration agencies are able to customise the allocations of ISBNs that they make to publishers. For example, a large publisher may be given a block of ISBNs where fewer digits are allocated for the registrant element and many digits are allocated for the publication element; likewise, countries publishing many titles have few allocated digits for the registration group identifier and many for the registrant and publication elements. Here are some sample ISBN-10 codes, illustrating block length variations.