A secondary source of information in a research on the American Civil War, in opposition to a primary or a tertiary source, is an account of the event written after the fact. For that reason, it can be considered as an interpretation or a discussion of a primary source, which is an original material such as a newspaper or a map. A secondary source about the Civil War could be, for example, Shelby Foote's The Civil War: A Narrative, or a biography such as Elizabeth Brown Pryor's Reading the Man: A Portrait of Robert E. Lee Through His Private Letters.