International Union Catalogs

At present hundreds of huge electronic union catalogs, library network catalogs and library consortium catalogs etc, (the majority based on the Z39.50 computer networking protocol, and linked to the TCP/IP network protocol for international web access) are major ongoing projects around the world in major public and academic libraries. Most of them, notably those in Europe, Japan and North America, have been completed and are up and running. Union catalogs are very valuable not just to catalogers, but also to library users, researchers, lecturers, teachers, politicians, writers, journalists, academics, biographers, booksellers, students etc. Also practically anyone making interlibrary loan requests in libraries (or librarians processing such requests) will find union catalogs invaluable.

Some electronic union catalogs are free to access (mostly those set up with government funds), while others require a paid subscription, especially those run by commercial companies. At present there is only one big global union catalog, the famous Worldcat, which is part of OCLC's First Search services. At the last count, over 45,000 libraries in over 83 countries, can be accessed with the Worldcat database.

During the research work for the first edition and second edition of, Library World Records, between 2003 and 2007, I used both Worldcat and several European union catalogs, in my search for specific books. Because I traveled to several European libraries during the research, being able to know if particular books I needed, for my book project, was in a library I was visiting the next day, proved invaluable and saved me a lot of precious time searching individual catalogs.

I am now adding all my saved data on European union catalogs, for this web page, as well as adding several other union catalogs from other continents. Feel free to submit the URL of any union catalog, not listed here. The libraries in the union catalog can be part of a town, city, county, region, consortium, network, state, province or country etc.

As a cataloger myself, my favourite OPACs are the Horizon OPAC, developed by Dynix; DRA OPAC from SIRSI; and Innopac OPAC from Innovative Interfaces, because these are among the few OPACs that lets catalogers add the following useful extras: colour photograph of the book's front cover, book summary, the table of contents of the book, reviews of the book by reviewers, and some extensive data (mini bio) on the author. All this takes the traditional (non-graphical & text-only) bibliographic data display in older versions of OPACs to the next level in 21st century technological capability.

In 1995, when the Internet was still very young (back then it was Netscape web browser) and Google not yet invented, I began to compile a list of all library-related websites that where begining to show up. By 2005, I had compiled over 1,930 websites, including this list of union catalogs. By 2010, I decided that with Google now advanced and Wikipedia available as well, there was no need to update the directory any more including this list of union catalogs, so since 2010 I no longer update this list of union catalogs, but you can still enjoy using it.

WARNING: many links are now outdated, since it was last updated in 2010.



Asia-Pacific region.


Middle East / Africa.

Link to Union Catalog.
Details: Combined catalog from publishers databases around the world, of forthcoming new books, those already published or out of print books. From Bowker. List only books in English.

Other cataloging tools to:

This is a huge collection of advanced reference tools, including MARC 21 codes for the cataloger.
ITS.MARC is an online copy cataloging resource of over 41 million records. It delivers two kinds of MARC records: bibliographic and authority. It is great tool to brush up your MARC cataloging skills. ITS.MARC Website Access.