Within the context of literature, a primary source is either an original literary work (i.e. Jane Austen's Mansfield Park) or personal information produced by the author (letters, diaries, manuscripts etc). If you're doing historical research, primary sources are those first-hand, eyewitness accounts that provide an insight into a particular period of history (i.e. The Diary of Anne Frank). Examples include oral histories, contemporary newspaper articles, film footage and government documents.