Definitions
Continuing resources are publications issued over time under the same title and with no predetermined conclusion. The term includes serials—which are print or non-print publications issued in parts, usually bearing issue numbers and/or dates—as well as other continuing resources that are updated by new material being seamlessly integrated into the existing content. Serials must be intended to continue indefinitely and include scholarly journals, magazines, newspapers, blogs, podcasts, annuals (such as reports, yearbooks, and directories), proceedings of conferences, transactions of societies, and monographic series. Other continuing resources include updating databases, updating online directories, repositories, and certain other updating websites.
International Standard Serial Numbering
The various and constant changes to which serials are subject, combined with the large growth in the world's publishing output, prompted the development of a standard (ISO 3297-1975; ANSI Z39.9-1979) for the identification of serials and other continuing resources: the International Standard Serial Number (ISSN).
A single ISSN uniquely identifies a title regardless of language or country in which it is published, without the burden of a complex bibliographic description. The ISSN itself has no significance other than the unique identification of a serial.
An ISSN is eight digits long. The ISSN is always displayed this way: ISSN 1234-5679. The first seven digits serve as the title number and the eighth is a check digit that provides an efficient means for discovering transcription errors. The system used for calculating the check digit sometimes requires a check number of 10, in which case, to prevent a nine-digit ISSN, the Roman numeral "X" is substituted.
For each serial or other continuing resource with an ISSN there is a corresponding "key title"—a unique form of the title established at the time of ISSN assignment. The publication’s title provides a benchmark: if the title of a serial or other continuing resource changes, a new ISSN must be assigned.
Administration of ISSN
The coordination of the ISSN is international, through the ISSN Network of over 90 ISSN centers worldwide. ISSN registration takes place at the national level in the country where serials and other continuing resources are published. The U.S. ISSN Center within the Library of Congress is the U.S. member of the ISSN network. The ISSN International Centre located in Paris coordinates the network. The U.S. ISSN Center is responsible for registering and providing ISSN for serials and other continuing resources published in the United States and its territories, and for promoting use of the ISSN.
Advantages of Use
The ISSN should be as basic a part of a serial or other continuing resource as the title. The advantages of using it are abundant and the more the number is used the more benefits will accrue.
- ISSN provides a useful and economical method of communication between publishers and suppliers, making trade distribution systems faster and more efficient.
- The ISSN results in accurate citing of serials and other continuing resources by scholars, researchers, abstracters, and librarians.
- As a standard numeric identification code, the ISSN is eminently suitable for computer use in fulfilling the need for file update and linkage, retrieval, and transmittal of data.
- ISSN is used in libraries for identifying titles, ordering and checking in, and claiming serials and other continuing resources.
- ISSN simplifies interlibrary loan systems and union catalog reporting and listing.
- The U.S. Postal Service uses the ISSN to identify certain publications mailed at periodicals rate.
- The ISSN is an integral component of the journal article citation used to monitor payments to the Copyright Clearance Center, Inc.
- All ISSN registrations are maintained in an international data base and are made available online in the ISSN Portal. The ISSN Portal and other products are described in a document maintained by the ISSN International Centre: ISSN products.
How to Obtain an ISSN
Instructions for U.S. publishers:
The assignment of the ISSN is free in the U.S. and there is no charge associated with its use. (However, the Library of Congress incurs substantial costs to staff and maintain the U.S. ISSN Center. Additionally, the Library of Congress is assessed a considerable fee to belong to the ISSN Network.)
In order to apply for an ISSN, applicants must first create an account in ISSN Uplink, the U.S. ISSN Center’s online application system, and enter the required information for each title requested. Applicants are prompted to provide URLs for online publications and attach scans for print or other physical formats (DVD, CD-ROM, flashdrive, etc.). Applications for titles available in print are also required to send hard copies by U.S. mail or private carrier to the U.S. ISSN Center using a mailing label that can be downloaded.
Except for microform reproductions, separate ISSN are generally required for serials and other continuing resources issued in different physical formats. Separate ISSN are also required for serials and other continuing resources issued in different language, geographic, or audience editions.
ISSN requests prior to publication are available under certain circumstances outlined in ISSN Uplink instructions. For pre-publication requests, a mock-up or artist's conception of the identifying parts of the publication should be added as an attachment when applying in Uplink. In these "v. 1, no. 1" cases, a follow-up sample issue of the actual serial must be sent directly to the U.S. ISSN Center after publication has begun. A mailing label can be downloaded from Uplink.
To fulfill its purpose, the ISSN should be displayed prominently on every issue, preferably in the top right corner of the cover of print publications or on title screens or cover screens of online publications. It is acceptable, however, for the number to appear elsewhere on the publication (usually in the masthead area). Various user groups—particularly the U.S. Postal Service—have specific printing regulations which must be adhered to.
If the serial or other continuing resource has an International Standard Book Number (ISBN) for the individual volumes within a series, in addition to the ISSN for the series as a whole, the two numbers should appear together, each with its own prefix. The ISSN should be printed right after the title of the series, both in books and in advertising pieces.
It is appropriate for both ISBN and ISSN to be assigned to certain other types of publications, most notably annuals and other directories or reference publications. The ISBN identifies the particular year or edition, the ISSN identifies the ongoing serial or continuing resource.
ISSN should appear in publisher's advertisements and catalogs, on the serials and other continuing resources themselves, and in all other places where details of books, serials and other continuing resources normally appear.
Changes Affecting ISSN
Serials and other continuing resources often undergo changes, many of which result in a change of title. When this occurs, a new ISSN must be assigned. The earlier ISSN is not discarded, however, because it is a permanent attribute of the serial when it was issued under the earlier title. To avoid printing an incorrect ISSN, publishers must use Uplink to apply for a new ISSN in advance of a title change, especially one affecting the cover title (which is often the source for the key title). The application process is the same as that for the original ISSN request. Other changes to a serial, such as those of place, publisher, and frequency do not affect the ISSN assignment. In any case of doubt, please contact the U.S. ISSN Center.
Display and careful use of the ISSN will help in the worldwide effort to make the number achieve its intended role as a valuable means of identifying serials and other continuing resources.
Last Updated: March 1, 2022
