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Primary, Secondary, and Tertiary Sources

Learn to distinguish primary, secondary and tertiary sources in the humanities and sciences.

What are primary sources?

Primary sources are original materials representing a wide range of events, ideas, and research experiments. They are contemporary to the time they are written, meaning they are written very close to the action or event they are describing.

When you use a primary source in a paper, think of them as the "ground zero" of resources.  The source you are looking at is where the original ideas you are seeking were recorded. You are getting as close to the event or idea you are researching as possible without actually being able to be there yourself.  For example, the Declaration of Independence is a primary source.  It is an original idea and creation.  

While the linked example is obviously not the original document (which is in the National Archives Building in Washington, D.C.), the text of that web page is the same as the original. Looking at the original document or creative work of art is the preferred option but obviously isn't always feasible.  Reproductions of original documents and works of art allow us to still use the information and ideas of the document without having to travel to see the original.

Use the tabs below to find examples of primary sources typically used in the Humanities and those in the Sciences.


To cite this LibGuide use the following templates:

APA: Northern Essex Community College Library. (Date updated). Title of page. Title of LibGuide. URL

MLA: Northern Essex Community College Library. "Title of Page." Title of LibGuide, Date updated, URL.