What Are Primary Sources? (text from UC Irvine Libraries https://www.lib.uci.edu/what-are-primary-sources)
Primary sources are documents, images or artifacts that provide firsthand testimony or direct evidence concerning an historical topic under research investigation. Primary sources are original documents created or experienced contemporaneously with the event being researched. Primary sources enable researchers to get as close as possible to what actually happened during an historical event or time period. A secondary source is a work that interprets or analyzes an historical event or period after the event has occurred and, generally speaking, with the use of primary sources. The same document, or other piece of evidence, may be a primary source in one investigation and secondary in another. The search for primary sources does not, therefore, automatically include or exclude any format of research materials or type of records, documents, or publications.