A primary source is "first-hand" information, or sources as close as possible to the origin of the information or idea under study.
An actual work of art, whether a painting or a building, is a primary source. Books written by the architect, such as a journal/diary/autobiography/letters are primary sources, as are newspaper and magazine articles written by someone who attended a building opening or a talk by an architect. Books and articles written by friends and associates during the architect's lifetime would also be primary sources.
Primary sources are contrasted with secondary sources, which are works that provide analysis, commentary, or criticism on the primary source. Reviews of art exhibits and events can be found in newspapers and some older magazines.
