The materials, evidence, or data used in your research are known as sources. As foundations of your research, these sources of information are typically classified into two broad categories: primary and secondary.

Primary Sources

A primary source provides direct or firsthand evidence about an event, object, person or work of art. Generally, primary sources are contemporary to the events and people described and show minimal or no mediation between the document/artifact and its creator. As to the format, primary source materials can be written and non-written, the latter including sound, picture, and artifact. Examples of primary sources include:

• personal correspondence and diaries

• works of art and literature

• speeches and oral histories

• audio and video recordings

• photographs and posters

• newspaper ads and stories

• laws and legislative hearings

• census or demographic records

• plant and animal specimens

• coins and tools

A secondary source, in contrast, lacks the immediacy of a primary record. As materials produced sometime after an event happened, they contain information that has been interpreted, commented, analyzed or processed in such a way that it no longer conveys the freshness of the original. History textbooks, dictionaries,encyclopedias, interpretive journal articles, and book reviews are all examples of secondary sources. Secondary sources are often based on primary sources.

Bear in mind, however, that primary and secondary sources are not fixed categories. The use of evidence as a primary or secondary source hinges on the type of research you are conducting. If the researcher of the 2000 presidential election were interested in people's perceptions of the political and legal electoral controversy, the Op/Ed columns will likely be good primary sources for surveying public opinion of these landmark events. Biographies often fall within both categories since primary sources were likely consulted heavily in the writing of a reliable account

Use Library of Congress subject heading to find primary materials in I-Share or any catalog. 

Example Subject Headings: