The purpose of encyclopedias to summarize the state of knowledge in a field of inquiry. (Enycyclopedias synthesize the secondary sources on a topic.) Use encyclopedias to find background information on your topic, and to familiarize yourself with what is already known on the topic. A good encyclopedia can be a valuable starting point for your research, and often contains recommendations for additional reading.

Three online reference collections that students often find useful are:

Below is a list of encyclopedias relevant to research for this course:

A bibliography is, in its most literal sense, a list of books. Many students are familiar with bibliographies from writing research papers, where a list of works cited is sometimes called a bibliography. In libraries, bibliographies serve an additional, important function in helping patrons identify books, journal articles, and other library resources. These bibliographies are usually centered on sources about a particular subject, and are often book-length themselves. Some bibliographies run to several volumes. For more information on bibliographies, please see our guide to Bibliography and Historical Research:

A catalog is similar to a bibliography with the difference being that a catalog lists books and other resources available for use or purchase at a specific place, or from a specific person or organization. Examples are library catalogs, catalogs of private collections, and booksellers' catalogs.

The most common reference sources for biographical information are biographical encyclopedias, and directories. Use the Library Catalog to find book-length biographies of individuals.

Listed here are sources of factual information, which can include almanacs, chronologies, factbooks, statistical compendia, and directories (directories that include personal information are included in the above section on biographies; directories listing places and businesses are listed separately below). Directories especially can be interesting as historical sources as they tend to be published serially (usually annually), and therefore provide a snapshot of the world during the year covered.