Primary Sources

Primary Sources

Definition of Primary Source

  • The meaning of the term "primary source" varies by scholarly discipline, but at the root, a primary source is a document that is studied by scholars in the field of study, while the documents that those scholars produce when they analyze, discuss and evaluate primary sources are known as "secondary sources."  Some fields also use terms like "teriary" or "educational" sources to describe works whose purpose is to index primary and/or secondary sources and prepare them for consumption by non-specialists.
  • In literature, a primary source is the work of literature itself. 
  • In religious studies, it may be a Koran, a hymnal, catechism or even a ceremony. 
  • In the arts, typical primary sources would be paintings, musical scores or recordings, and scripts.
  • Science typically uses the term "primary literature," which refers to things like lab notebooks, biosequence or remote sensing data, patents, and original research articles documenting scientific experiments, as opposed to articles whose purpose is to synthesize or interpret others' experimental data.  See for further information about primary literature in the sciences.
  • In the field of history, and in the historical study of other fields (history of science, historical criticism of literature, etc.), a primary source is a document that gives evidence of historical events or conditions, created at the time being studied, by someone with firsthand knowledge. 


    • It can take the form of a diary or letter, photograph, manuscript, census list, tax ledger, Congressional debate, court record, advertisement, telegram, or even something as simple as a grocery receipt.
    • Newspaper, radio and TV news reports are sometimes considered primary sources, in the sense that they are produced during the historical period, but historians point out that reporters may not have the level of knowledge about the events they describe that the historical actors themselves have, and are already engaging in the filtering and analyzing that characterizes secondary sources. 
    • To make things even more complicated, the tertiary literature of a period (textbooks, handbooks etc.) can be used as primary source, if the goal is to study the educational practice of a period, or "what the common person might have known," rather than to ascertain facts about a particular historical event.

    See the Primary Sources for Historical Research Subject Guide for further examples and links.

Finding primary sources that are catalogued in MERLIN:

  • Use the advanced search.  Use one line of your search to string together keywords that are used in the subject headings for many types of primary sources.  You may eliminate any of the terms that are not appropriate for your topic.  Separate each term with the word OR.
    sources or correspondence or diaries or interviews or sermons or document* or…
  • Use date limits in the advanced search.  For instance: to find books, pamphlets and documents written about alcohol during the first half of the 19th century, you might do a search in MERLIN for alcohol* or beer* or liquor* and limit the search to dates between 1799 and 1850.

Other Sources of Primary Documents

  • Databases identified by librarians as containing or indexing primary sources
  • Unpublished sources
    Search ArchiveGrid for objects, manuscripts and other unpublished sources stored in archives around the world
  • Digitized collections available online


    • Older versions of Web sites: Internet Archive
    • In Google, add search terms like those you would use to find books in MERLIN, above.  Also try terms like digitized, digital, online, archive, archival, e-archive, documents, museum, library