User:Andrew Gray/ISBN

The International Standard Book Number (ISBN) is a ten- or thirteen-character code used as an identifier for commercially published books. Originally produced in the late 1960s for the British publishing industry as the nine-digit Standard Book Number, the system became widespread as the ten-digit ISBN in the 1970s and 1980s, and is today one of the most widely used standard identifiers for books worldwide. From 2005, the standard was extended to thirteen characters (ISBN-13), with the older system defined as ISBN-10; the migration concluded in 2007, and all currently issued ISBNs are thirteen characters long. The two systems are directly convertible - each ISBN-10 has a corresponding ISBN-13, and vice versa - and many books published during the transitional period carry both.

ISBNs are theoretically unique to specific editions of books, but this principle is not always adhered to; some are reused for subsequent editions, while others are accidentally assigned twice by publishers. Different bindings of the same edition (eg, hardcover vs. paperback) are normally given separate ISBNs, and an edition jointly produced by multiple publishers may be issued ISBNs by each of them.

Similar standard codes include the International Standard Serial Number (ISSN), for periodicals, and International Standard Music Number[ (ISMN), for printed scores.

Usage
ISBNs are usually printed on the title page verso of a book, along with cataloguing in publication data where present. If the book has a UPC/EAN barcode - usually on the back cover - the ISBN is usually printed alongside this. Some older books included the ISBN on the inside flaps of a dust jacket, and others (particularly Penguin paperbacks) would print the ISBN/SBN on the spine.

(...)

Occasionally, a book may appear 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.

R.R. Bowker is the U.S. Agency of the International Standard Book Numbering Convention, as approved by the International Organization for Standardization. As such, it is the originator of ISBNs for U.S.-based publishers. Authors of self-published books can purchase an ISBN for $125.00. Publishers in other countries can only obtain ISBNs from their local ISBN Agency, a directory of which can be found on the International ISBN Agency website.

Publishers and libraries have varied policies about the use of the ISBN check digit. Publishers sometimes fail to check the correspondence of a book title and its ISBN before publishing it; that failure causes book identification problems for libraries, booksellers, and readers.

Most libraries and booksellers display the book record for an invalid ISBN issued by the publisher. The Library of Congress catalogue contains books published with invalid ISBNs, which it usually tags with the phrase "Cancelled ISBN". However, book-ordering systems such as Amazon.com will not search for a book if an invalid ISBN is entered to its search engine.

History
The 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others 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. (However, the 9-digit SBN code was used in the United Kingdom until 1974.) Currently, the ISO's TC 46/SC 9 is responsible for the ISBN. The ISO on-line facility only refers back to 1978.

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

Structure
The ISBN is thirteen digits long if assigned after January 1, 2007, and ten digits long if assigned before 2005; during the transitional periods, many publishers issued items with both. During the 1960s, nine digit SBNs were used, and some publishers continued to print "ISBN"s with nine digits into the late 1970s; these can be converted to a ten-digit SBN by adding a leading zero.

The ISBN consists of 4 or 5 parts:




 * 1) for a 13-digit ISBN, a GS1 prefix: 978 or 979 (indicating the industry; in this case, 978 denotes book publishing)
 * 2) the group identifier, (language-sharing country group)
 * 3) the publisher code,
 * 4) the item number (title of the book), and
 * 5) a checksum character or check digit.

Other than the check digit, no part of the ISBN has a fixed number of digits. The parts are separated with either a hyphen or a space, though it is common to see the ISBN rendered as a single ten or thirteen digit string with no separation; this is often used for internal data processing.

Group identifier
The group identifier is a 1 to 5 digit number. The single digit group identifiers 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, 7 for People's Republic of China. An example 5 digit group identifier is 99936, for Bhutan. The allocated group IDs are: 0–5, 600–617, 7, 80–94, 950–989, 9927–9989, and 99901–99967. Some catalogs include books that were published with no ISBN but add a non-standard number with an as-yet unallocated 5-digit group such as 99985; this practice is not part of the standard. Books published in rare languages typically have longer group identifiers.

The original standard book number (SBN) had no group identifier, but affixing a zero (0) as prefix to a 9-digit SBN creates a valid 10-digit ISBN. Group identifiers form a prefix code; compare with country calling codes.

Publisher code
The national ISBN agency assigns the publisher number (cf. the category:ISBN agencies); the publisher selects the item number. Generally, a book publisher is not required to assign an ISBN, nor is it necessary for a book to display its number (except in China; see below). However, most book stores only handle ISBN-bearing merchandise.

A listing of all the 628,000 assigned publisher codes is published, and can be ordered in book form (€558, US$915.46). 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 group identifier code, several digits for the publisher, and a single digit for the individual items. Once that block of ISBNs is used, the publisher may receive another block of ISBNs, with a different publisher number. Consequently, a publisher may have different allotted publisher numbers. There also may be more than one group identifier used in a country. This might occur if a popular identifier has used up all of its numbers. The cited list of identifiers shows this has happened in China and in more than a dozen other countries.

By using variable block lengths, a large publisher will have few digits allocated for the publisher number and many digits allocated for titles; likewise countries publishing much will have few allocated digits for the group identifier, and many for the publishers and titles. Here are some sample ISBN-10 codes, illustrating block length variations.
 * {| class="wikitable"

! ISBN || Country or area || Publisher
 * 99921-58-10-7 || Qatar || NCCAH, Doha
 * 9971-5-0210-0 || Singapore || World Scientific
 * 960-425-059-0 || Greece || Sigma Publications
 * 80-902734-1-6 || Czech Republic; Slovakia || Taita Publishers
 * 85-359-0277-5 || Brazil || Companhia das Letras
 * 1-84356-028-3 || English-speaking area || Simon Wallenberg Press
 * 0-684-84328-5 || English-speaking area || Scribner
 * 0-8044-2957-X || English-speaking area || Frederick Ungar
 * <tt>0-85131-041-9</tt> || English-speaking area || J. A. Allen & Co.
 * <tt>0-943396-04-2</tt> || English-speaking area || Willmann–Bell
 * <tt>0-9752298-0-X</tt> || English-speaking area || KT Publishing
 * }
 * <tt>0-684-84328-5</tt> || English-speaking area || Scribner
 * <tt>0-8044-2957-X</tt> || English-speaking area || Frederick Ungar
 * <tt>0-85131-041-9</tt> || English-speaking area || J. A. Allen & Co.
 * <tt>0-943396-04-2</tt> || English-speaking area || Willmann–Bell
 * <tt>0-9752298-0-X</tt> || English-speaking area || KT Publishing
 * }
 * <tt>0-943396-04-2</tt> || English-speaking area || Willmann–Bell
 * <tt>0-9752298-0-X</tt> || English-speaking area || KT Publishing
 * }
 * <tt>0-9752298-0-X</tt> || English-speaking area || KT Publishing
 * }

Pattern
English-language publisher codes follow a systematic pattern, which allows their length to be easily determined, as follows:

Check digits
A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message. While the remainder of the ISBN is in base 10 and uses the digits 0-9, the check digit is in base 11 and uses 0-9, plus X (representing ten).

Due to the presence of a different prefix, corresponding ISBN-10s and ISBN-13s will have different check digits.

(... do we need the detailed calculations? ...)

EAN format used in barcodes, and upgrading
Currently the barcodes on a book's back cover (or inside a mass-market paperback book's front cover) are EAN-13; they may have a separate barcode encoding five digits for the currency and the recommended retail price. The number "978", the Bookland "country code", is prefixed to the ISBN in the barcode data, and the check digit is recalculated according to the EAN13 formula (modulo 10, 1x and 3x weighting on alternate digits).

Partly because of an expected shortage in certain ISBN categories, the International Organization for Standardization (ISO) decided to migrate to a thirteen-digit ISBN (ISBN-13). The process began January 1, 2005 and was planned to conclude January 1, 2007. As of 2011, all the 13-digit ISBNs begin with 978. As the 978 ISBN supply is exhausted, the 979 prefix will be introduced. This is expected to occur more rapidly outside the United States. Originally, 979 was the Musicland code for musical scores with an ISMN. However, ISMN codes will differ visually as they begin with an "M" letter; the bar code represents the "M" as a zero (0), and for checksum purposes it will count as a 3.

Publisher identification code numbers are unlikely to be the same in the 978 and 979 ISBNs, likewise, there is no guarantee that language area code numbers will be the same. Moreover, the ten-digit ISBN check digit generally is not the same as the thirteen-digit ISBN check digit. Because the EAN/UCC-13 is part of the Global Trade Item Number (GTIN) system (that includes the EAN/UCC-14, the UPC-12, and the EAN-8), it is expected that ISBN-generating software should accommodate fourteen-digit ISBNs.

Barcode format compatibility is maintained, because (aside from the group breaks) the ISBN-13 barcode format is identical to the EAN barcode format of existing ISBN-10s. So, migration to an EAN-based system allows booksellers the use of a single numbering system for both books and non-book products that is compatible with existing ISBN-based data, with only minimal changes to information technology systems. Hence, many booksellers (e.g., Barnes & Noble) migrated to EAN barcodes as early as March 2005. Although many American and Canadian booksellers were able to read EAN-13 barcodes before 2005, most general retailers could not read them. The upgrading of the UPC barcode system to full EAN-13, in 2005, eased migration to the ISBN-13 in North America. Moreover, by January 2007, most large book publishers added ISBN-13 barcodes alongside the ten-digit ISBN barcodes of books published before January 2007.