A list of union catalogs:
During the research work on my latest book, Library World Records, I used both Worldcat and several European union catalogs, in my search for specific books, because I travelled to several European libraries, being able to know if particular books I needed, for my book project, was in a library I was visiting, proved invaluable and saved me a lot of time searching individual catalogs. [INFO CONNECT: Union Catalogs of the World.]The author, Godfrey Oswald, notes the utility of WorldCat as the only 'big global union catalog'. Spotted in Catalogablog which spotted it in ResourceShelf.