Recognizing secondary sources

Secondary sources were created by someone who did not experience first-hand or participate in the events or conditions you’re researching. For a historical research project, secondary sources are generally scholarly books and articles.

A secondary source interprets and analyzes primary sources. These sources are one or more steps removed from the event. Secondary sources may contain pictures, quotes or graphics of primary sources.

Some types of secondary source include:  Textbooks; journal articles; histories; criticisms; commentaries; encyclopedias 

Examples of secondary sources include:

For a historical research project, secondary sources are usually scholarly books and articles, but as you can see from this list there are other possibilties.

Find Secondary Sources

History of Science, Technology and Medicine (Harvard Login)  (1975- ) is an index of books, book chapters, and journal articles. Some social sciences material is included. 

  • HSTM is an amalgamation of four separate indexes with four different subject term systems; study the results of keyword searches to be sure that you know the proper subject terms for your topic in each of the, possibly four, relevant component databases. For example, the Wellcome Bibliography uses "Contraception" but the Isis Current Bibliography uses "Birth control".
  • If you want to limit the coverage of your sources to a particular era, put one of these terms in a search box: Antiquity or Ancient - “Greek and Roman” - “Middle Ages” or medieval - 13th  century - 14th century - 15th century - 16th century - 17th century - 18th century - 19th century - 20th century
  • More detailed information about the use of this complex database.

ISISCB Bibliographic Resources in the History of Science, Technology and Medicine indexes the Isis Current Bibliography.  Search results extend back to 1970.  It also offers a browse of the Isis Cumulative Bibliographies (1913-1975). Search ISISCB Explore

PubMed (Harvard Login for full text access) (1947- ) is the National Library of Medicine's index to biomedical journal articles.

  • To limit to historical sources, attach the phrase (in"") "historical article" to your search. Example: "Psychology, clinical" and "historical article".
  • Be sure to look for MeSH (Medical Subject Headings) on pertinent records by scrolling down past the abstracts. (Not all records in PubMed have MeSH terms.) Subject headings can help you get to more relevant records and/or can be helpful keyword suggestions.

America: History and Life (Harvard login) is the primary bibliographic reference to the history of the United States and Canada from prehistory to the present.

Historical Abstracts (Harvard Login) is a reference guide to the history of the world from 1450 to the present (excluding the United States and Canada, which are covered in America: History and Life, above).

  • Both allow coverage date limitations as well as publication date limitations, Can usually use LC terms, not always 

Bibliography of British and Irish History (Harvard Login) provides bibliographic data on historical writing dealing with the British Isles, and with the British empire and commonwealth, during all periods for which written documentation is available - from 55BC to the present.

  • At the link above, choose BBIH from the top row of options.

The Forest History Society Research Portal offers over 45,000 citations to published items on environmental history, over 30,000 photographs, and other material.

Web of Science Citation Indexes (Harvard Login) (for historical articles1956- ) includes articles in all areas of science. You can use the Cited Reference Search in Web of Science to find secondary source articles that cite a specified secondary or primary source article or book. More information.

Library Guide to the History of Science Your guide to the History of Science at Harvard. It has more extensive lists of resources and tools than this introductory guide does.

Finding Bibliographies

There may already be a detailed list of sources, a bibliography, for your topic. Bibliographies don't always come at the end of a paper- many are independent works of their own, full of recommended sources on any given topic.

For example:

Look for specialized subject bibliographies: search, e.g., <"science and state" AND China AND bibliography>  in HOLLIS and WorldCat (advanced search). Note:The word Bibliography must be searched as a Subject keyword.

If you find an older article or book in a bibliography, you can use the Cited Reference Search in Web of Science to find more recent articles by seeing who has cited it.   If you have a bibliography of primary sources, then the Web of Science can be used to find secondary sources that cite a specified primary source. See Searching the Citation Indexes (Web of Science).