"A primary source is a document, image, or artifact that provides evidence about the past. It is an original document created contemporaneously with the event under discussion. A direct quote from such a document is classified as a primary source. A secondary source is a book, article, film, or museum that displays primary sources selectively in order to interpret the past." Robert C. Williams, The Historian's Toolbox: A Student's Guide to the Theory and Craft of History, p.58
Primary sources enable the researcher to get as close as possible to what actually happened during a historical event or time period. A primary source reflects the individual viewpoint of a participant or observer. Many primary sources are unique and can only be found in one library or manuscript collection in the world. Fortunately, many have also been copied onto microfilm, published, reissued, translated, or, in some instances, published digitally on the web. Remember, however, your best source may not be on the web.
Some examples of primary sources include: