primary literature

Primary literature refers to original documents and objects created at the time of a historical event or study. These are the raw materials of research, offering direct experience and firsthand accounts. Examples include diaries, letters, photographs, and official records.1

In contrast, secondary literature, or secondary sources, are accounts that retell, analyze, or interpret events after the fact, often at a distance from the original occurrence. These sources are based on primary materials but are not original records themselves. The development of printing and publishing industries has led to a vast amount of primary literature, necessitating tools like abstracts and indexes to navigate it.23