Primary sources are sources of information which help to inform us on the past, because they serve as evidence. They were created contemporary to, or very near to, the event or time period being studied, and thus they are representative.
Archives and other special repositories are great places to find primary sources because their location in an archives helps to ensure their authenticity - the fact that a primary source is in an archives means that experts have collected and considered the source material. We also provide some context for you, and explain the creator.
Primary sources are found in a variety of formats. In the Archives Dept. at UWM Libraries, we have all the formats (and more) explained on this page.