Learn about the Library of Congress Classification System (LC).
Catalog of 43 million books and other materials for libraries worldwide. This is the Big One!
WorldCat.org is a great resource for locating unique, trustworthy materials that you often can’t find anywhere except in a library. And by connecting thousands of libraries’ collections in one place, WorldCat.org makes it easy for you to browse the world’s libraries from one easy search box.
During the past 50+ years, thousands of libraries have entered their information about millions of books, magazines, movies, songs, maps, genealogical records, research theses and so much more into WorldCat. And not just the physical items you could find when you visit a library, but many kinds of digital content like open-source e-books, articles, downloadable audiobooks, and photos. You can also find article citations with links to full text, authoritative research materials, one-of-a-kind documents and photos of local or historic significance, and digital versions of rare items that aren’t generally available to the public.
WorldCat.org is supported by OCLC, a nonprofit global library organization that provides shared technology services, original research, and community programs so libraries can better fuel learning, research, and innovation.