What are Primary & Secondary Sources?

Primary sources are the main text or work that you are discussing (e.g. a sonnet by William Shakespeare; an opera by Mozart); actual data or research results (e.g. a scientific article presenting original findings; statistics); or historical documents (e.g. letters, pamphlets, political tracts, manifestoes). ["What is a Source?" Recognizing and Avoiding Plagarism. Cornell University. College of Arts and Sciences.]

Secondary sources are "books, periodicals, web sites, etc. that people write using the information from primary sources. They are not written by eyewitnesses to events, for instance, but use eyewitness accounts, photographs, diaries and other primary sources to reconstruct events or to support a writer's thesis about the events and their meaning. Many books you find in the Cornell Library Catalog are secondary sources." [Finding Primary Sources: A Web-Based Guide]

Finding Primary Sources

Here are two excellent guides to finding primary sources:

Finding Primary Sources: A Web-Based Guide  from Cornell University Library. A brief guide.

Finding Historical Primary Sources from the University of California at Berkeley Library.  This is an excellent, detailed overview--although geared toward research at UC Berkeley, most of the information is highly relevant to Cornell researchers as well.