A primary source is a document, speech, or other sort of evidence written, created or otherwise produced during the time under study, that provides direct, first-hand knowledge of an event or experiment. Primary sources offer an inside view of a particular event.
What counts as a primary source, and is appropriate for inclusion in your research, varies by discipline. In the humanities and social sciences, primary sources may include manuscripts, diaries, newspaper accounts, original works of art, photographs and others. In the sciences, primary sources may include journal articles describing experimental results, patents, data sets, technical reports, or theses and dissertations. In each case the primary source is generally the initial publication of the material.
If you need help finding primary sources, check out our Library Do-It-Yourself tutorial Searching for Primary Sources.
For further details and examples, check out Primary, secondary, and tertiary sources from the Virginia Tech Libraries.