In some cases, you may wish to interpret as primary sources texts that originally were created as scholarly secondary sources.  For example, if you are investigating the eugenics movement in the United States in the early twentieth century, you could look at articles on the topic that were published in academic journals in the 1910s and 1920s.

Books in Primo are assigned Library of Congress Subject Headings.  In many ways, subject headings are a form of tagging, in that they represent the content of the material and provide ways for you to efficiently locate more materials that are conceptually related. 

Library of Congress Subject Headings are also quite useful for discovering primary sources. The following subheadings usually are added to indicate that the material is a primary source: sources, personal narratives, correspondence, diaries, manuscripts, or notebooks.  Once you've discovered the subject heading for secondary sources, try adding one of the primary source subheadings to see what you find.  Here are some examples:

Secondary source subject heading:  Chinese Americans -- History
Primary source subject heading:   Chinese Americans -- History -- Sources.

Secondary source subject heading: United States -- History -- Civil War, 1861-1865.
Primary source subject heading: United States -- History -- Civil War, 1861-1865 -- Personal narratives, Confederate.

Academic libraries and historical museums often try to digitize primary source collections held in their archives and special collections in order to make them available to the widest possible audience.

This is only a sampling of the collections out there, just to get you started! 

Government documents from all three branches can be extraordinarily rich primary sources. 

In addition, here are a few key sites for identifying and locating govenment documents:

• GPO's Federal Digital System (FDsys)
  Provides public access to information submitted by Congress and federal agencies.
• HathiTrust Digital Library
  A digital collection of print materials made available online by member libraries. Not all content is available to Puget Sound users, but many government documents are accessible within HathiTrust since they are Public Domain materials.
• National Security Archive
  An independent non-governmental research institute and library located at The George Washington University, the Archive collects and publishes declassified documents obtained through the Freedom of Information Act.
• GovTrack.US
  GovTrack.us is a tool that tracks the activities in the U.S. Congress, promoting and innovating government transparency and civic education through novel uses of technology. You'll find here the status of U.S. federal legislation, voting records for the Senate and House of Representatives, information on Members of Congress, district maps, as well as congressional committees and the Congressional Record.