Union Catalog(ue)s in Western Libraries

Kevin S. Hawkins


Definitions adapted from the Online Dictionary of Library and Information Science (ODLIS) and other sources.

library catalog
describes bibliographic items. First we had card catalogs, then OPACs, then WebPACs. Since card catalogs and OPACs are almost extinct in the West, we just use "library catalog" to refer to the online graphical interface. Searching is free.
union catalog
originally print publications (such as the National Union Catalog, pre-1956 Imprints), often produced as national bibliographies. Today, records from multiple libraries are stored in a central location. Most union catalogs are subscription-based.
virtual union catalog
has one interface for searching multiple catalogs at the same time using Z39.50 (ISO 23950) or ZING. Searching is free.
index or abstracting service
a print publication providing access to articles or other contents below the level of a bibliographic item
bibliographic database
subject-based indexes in electronic format. They don't use a MARC format. Might be freely available or subscription-based.
multiple bibliographic databases combined together, stored in a central location. Subscription-based or freely available.
federated searching / metasearching / cross-database search / parallel search
searching multiple bibliographic databases and maybe also library catalogs at the same time. This is not quite the same as metasearching done on the Web. Metasearch engines are commerical web search engines that return results from multiple regular search engines.
cooperative cataloging
sharing MARC records through a bibliographic utility to save on cataloging costs
bibliographic utility
a service used by libraries to share records, or a computer program for working with MARC records or bibliographic citations

An asterisk (*) indicates that a resource is not freely available online.

There are a lot of resources resembling union catalogs. I group them into four categories, as shown below for Russia and the West.

In Russia

  1. Sometimes one library that lets you search other libraries' catalogs at the same time:
  2. But a real union catalog is independent of any particular library:
  3. Bibliographic utility
  4. Virtual union catalogs

In the West

Records created by Western libraries usually transliterate Cyrillic to the Latin script. The records might also have Cyrillic characters, but you should search in transliteration, omitting diacritical marks, for greater recall. For example, see

  1. Sometimes one library that lets you search other libraries' catalogs at the same time:
  2. Union catalogs
  3. Bibliographic utilities
  4. Virtual union catalogs

Other lists of catalogs

There are many lists online.

Other useful free sources on library collections