Only a select number of important research library catalogs are listed on this page. For the most comprehensive listing consult Libdex. (And don't forget to check the Dartmouth Library Catalog first.)
Please note also that the distinction between "catalogs" and "databases" is not always straightforward and easy. When in doubt, look at the Databases tab in the library catalog (located next to the tabas for Keyword, Title, Author, and Subject).
The most comprehensive and convenient source for verifying (and requesting!) books our library does not own. Includes a direct link for Interlibrary Loan.
Major search engines or groupings
Center for Research Libraries
CRL is a consortium of North American universities, colleges, and independent research libraries. The consortium acquires and preserves traditional and digital resources for research and teaching and makes them available to member institutions through interlibrary loan and electronic delivery.
The European Library
Formerly: Gabriel: The Gateway to Europe's National Libraries. Convenient access point for individual European national libraries.
Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research. Use Google Scholar to find articles from a wide variety of academic publishers, professional societies, preprint repositories and universities, as well as scholarly articles available across the web.
KVK: Karlsruher virtueller Katalog (Germany, and more)
An increasingly sophisticated search engine that makes it possible to search most major library catalogs in the German-speaking countries simultaneously. More catalogs are being added, including catalogs such as the British Library, the Bibliotheque nationale, and even the Library of Congress.
LANIC (Latin America)
Libraries and archives in Latin America
MELVYL (University of California)
Led by Berkeley and UCLA, the UC system has a major research collection. This catalog allows you to search the entire University of California collection simultaneously.
Western European Library Catalogs on the Internet
An excellent selection.
Major individual research library catalogs
HOLLIS (Harvard University )
Note that the libraries listed below participate in the Borrow Direct service. It is sometimes easier to find books in individual catalogs than via the Borrow Direct interface.