Books are often considered secondary sources, analyzing or recounting events after they have occurred. However, there are instances in which printed texts can serve as valuable primary sources. Autobiographies, newspapers, memoirs and original documents are all considered primary sources. In addition, books can be considered primary sources when they are analyzed based on the period they come from, rather than the content provided. For example, a book from the 18th century is likely to be considered a secondary source in terms of the content, but can be utilized as a primary source based on the style and the language used when considering 18th-century literature.
Films, maps, works of art and photographs are all excellent primary sources. Representing the original place in time in which the events take place, visual materials are valuable as primary resources. Information from visual resources can be of two types: both directly related to the explicit message conveyed by the creator, as well as insight gathered by the researcher regarding the creator's view and choices expressed through the creation.
Historical artifacts, such as articles of clothing, military medals, tools and toys all offer valuable information from their respective time period. Artifacts may also be naturally occurring, such as hair and bone fragments, making them a unique category of primary sources. Wartime artifacts are commonly utilized as primary sources, offering insight into the culture of the time and how it was affected by conflict.
Sound recordings, music, speeches and recorded theater are all examples of how audio recordings can serve as primary sources. Audio recordings are extremely valuable as primary sources, in that they can offer an explicit look at an event exactly as it occurred.
Not every primary source must be recorded in writing, video or audio and accessed by researchers long after the fact. Many important events can be researched through the oral history recounted by those who witnessed it. Interviews, anecdotes and other types of oral history all serve as direct primary sources. The onset of tape recorders and other such recording technology have allowed for the direct creation of primary sources by researchers.