Secondary sources are less easily defined than primary sources. Generally, they are accounts written after the fact with the benefit of hindsight. They are interpretations and evaluations of primary sources. Secondary sources are not evidence, but rather commentary on and discussion of evidence.
- Bibliographies (also considered tertiary);
- Biographical works;
- Commentaries, criticisms;
- Dictionaries, Encyclopedias (also considered tertiary);
- Histories;
- Journal articles (depending on the disciple can be primary);
- Magazine and newspaper articles (this distinction varies by discipline);
- Monographs, other than fiction and autobiography;
- Textbooks (also considered tertiary);
- Web site (also considered primary).