For help with HISTORY primary sources beyond specific History of Science topics, see: History & Primary Sources Research Guides, including Primary Sources Guide by Laurie Scrivener

A primary source is usually a record made at the time of an event by participants or by firsthand observers, but a primary source might also be created many years after the event in the form of an autobiography, memoir, oral history, published papers, etc. (For example, The Collected Works of Abraham Lincoln was originally published in 1953, long after Lincoln's death.)

Examples include, but are not limited to:

• contemporary newspaper or magazine accounts
• diaries, memoirs, or autobiographies
• correspondence
• congressional hearings
• fliers, like this from the National Library of Medicine:
  
• government reports
• government/organizational archives
• manuscripts (the papers of an individual or family)

Primary sources can be very different for different subjects. If you are writing a paper about an early female physician, for example, then her diary would be a primary source. If you are studying mid-twentieth century diplomatic history between the United States and Iraq, State Department records (such as Confidential U.S. State Department Central Files: Iraq, 1955-1959, available on Microfilm 498) would be a primary source.

If you are unsure what constitutes a primary source for your class, ask your instructor for some ideas. Also see this site from Yale University and this one from the University of Illinois for helpful hints on finding primary sources.