Using historical materials Historians divide their materials into primary and secondary sources. Primary sources are documents from the time being studied. Books, newspaper articles, letters, diary entries, movies, speeches or photographs can all be primary sources. Primary sources are documents from the time you are studying.
Secondary sources are materials produced by people in a later period.
For example, Theodore Roosevelt's speeches are primary sources . Edmund Morris' 1982 biography of Roosevelt is a secondary source. Newspapers from 1967 are primary sources for the study of the sixties, and especially the study of 1967. But any book or magazine article or movie published much after 1967 is a secondary source. There are a few more complicated cases.