What type of source is a letter from a survivor considered?

A letter from a survivor is classified as a primary source because it provides direct, first-hand accounts of personal experiences or events. Primary sources are original documents or materials that were created during the time under study or as a result of the events being investigated. In this case, the letter reflects the thoughts, emotions, and experiences of the survivor at the time they wrote it, offering valuable insight into their perspective and the historical context in which they lived.

In contrast, secondary sources analyze, interpret, or summarize information from primary sources, while tertiary sources compile and organize information from secondary sources. Quaternary sources are not commonly recognized in academic contexts and do not apply to this scenario. Thus, the nature of the letter as a personal and original document firmly positions it as a primary source.