Searching Multiple Libraries at Once
Worldcat.org or WorldCat (old First Search interface)
Includes more than 50 million records of books and other materials held in thousands of academic, public, special and national libraries around the world.
Catalogue Collectif de France (CCFR)
Unified search interface for libraries in France.
Consortium of University Research Libraries (COPAC)
Access to the merged online catalogues of 24 of the largest university research libraries in the UK and Ireland, plus the British Library and the National Library of Scotland.
Il Servizio Bibliotecario Nazionale (SBN)
Karlsruher Virtueller Katalog
Allows users to simultaneously search library catalogs from Germany, Austria, and Switzerland, as well as major catalogs worldwide.
Karlsruher Virtuelle Katalog (English)
iConn (formerly reQuest)
Unified search interface for library catalogs in Connecticut.