020  International Standard Book Number (R)

Definition

Contains the International Standard Book Number (ISBN). Use for canceled ISBNs, invalid ISBNs, Standard Book Numbers (SBNs), and terms of availability.

An ISBN is a unique number assigned to a resource by its publisher. Each ISBN is a 10- or 13-digit number and has four parts: the language group of the country of publication, the publisher, the title, and the check character.

Thirteen-digit ISBNs must begin with either 978 or 979 (a 13-digit EAN beginning with 978 or 979 may be input as a valid ISBN).

If printed in a book, catalog, or bibliography, these four parts are usually separated by hyphens, periods, or spaces. Do not enter the hyphens, periods, or spaces.

Note: If the final character is a lowercase x, enter an uppercase X.

Use the following guidelines for entering multiple ISBNs:

• Enter each valid ISBN in a separate 020 field

• If a book has ISBNs for both hard cover and paperback editions and if the publishers are the same, enter each ISBN in a separate 020 field

  020			0198702337 ǂq (hbk.)
  020			0198702345 ǂq (pbk.)

• If you are cataloging a multipart resource as a set, enter both the numbers for the set and the individual parts when available. Enter the number for the set first.

• When recording a valid and an invalid ISBN, record the valid ISBN first

  020			0769221076 ǂq (score)
  020			9780769221076 ǂq (score)
  020			0769221645 ǂq (part)
  020			9780769221649 ǂq (part)
  300			1 score (43 pages) + 1 part (14 pages) ; ǂc 30 cm

  020			0769221076 ǂq (score)
  020			9780769221076 ǂq (score)
  020			ǂz 0769221645 ǂq (part)
  020			ǂz 9780769221649 ǂq (part)
  300			1 score (43 pages) ; ǂc 30 cm

• Invalid ISBNs may be entered in a single 020 field with repeated subfields ǂz; however, OCLC recommends entering each invalid ISBN in a separate 020 field. For information on invalid ISBNs, see ǂz Canceled/invalid ISBN section below.
  

Some resources contain SBNs. They are the forerunner of modern ISBNs and are nine digits in length. If the resource was published in Australia, Canada, New Zealand, South Africa, the United Kingdom, the United States, or Zimbabwe, enter an initial 0 before the SBN). Enter the SBN in subfield ǂa. Enter SBNs from other countries in subfield ǂz.

For example, if the SBN is 717803139, enter:

The final character of an ISBN is a calculated check character, either 0-9 or X. It is used to identify and eliminate typographical errors.

When you validate a record containing field 020, the system checks subfield ǂa to verify that the content and length of the ISBN are correct and that the check character matches the calculated check character.

If there is an error in the ISBN (e.g., it is too long or too short, has an incorrect character in any position, or an incorrect value in the check digit), the system displays an error message with the ISBN remaining in subfield ǂa. If you made a typographical error, correct the ISBN and validate the record again. If the error message appears again and you transcribed the ISBN exactly, the ISBN is in error. Enter the ISBN in subfield ǂz.

If a record contains corresponding 10- and 13-digit ISBNs and you delete one, the system will regenerate the one you deleted and add it to the record. To avoid this situation, delete both ISBNs when editing locally.

1st Indicator

Undefined. The 1st indicator position is undefined and contains a blank.

	Undefined

2nd Indicator

Undefined. The 2nd indicator position is undefined and contains a blank.

	Undefined

Subfields

Punctuation

In records containing punctuation, enclose data in a single occurrence of subfield ǂq in parentheses. Enclose data in multiple occurrences of subfield ǂq in one set of parentheses and separate individual occurrences of subfield ǂq with a space, semicolon, space. Omit any punctuation from the end of the field unless it ends with an ellipsis, hyphen, closing parenthesis, exclamation point, question mark, or period following an abbreviation.

Indexing

For indexing and searching information, see Searching WorldCat Indexes, field 020.

MARC 21

For more information, including content designator history, see MARC 21 Format for Bibliographic Data, field 020.