Types of Congressional publications included in the Serial Set (text taken from U.S. Congressional Serial Set: What It Is and Its History by Virginia Saunders).

• Reports - (Senate & House)
  Reports of Congressional Committees concerning proposed legislation and/or contain findings on matters under investigation.
• Senate Executive Reports
  Reports of the Committee on Foreign Relations relating to Treaties between the United States and foreign nations which have been submitted to the U.S. Senate for ratification, or are reports of various Senate Committees regarding nomination of individuals.
• Senate Executive Documents
  Reports of the Committee on Foreign Relations relating to Treaties between the United States and foreign nations which have been submitted to the U.S. Senate for ratification, or are reports of various Senate Committees regarding nomination of individuals.
• Senate Treaty Documents
  Contain the text of a Treaty as it is submitted to the U.S. Senate for ratification by the President of the United States. Numbered consecutively from the 1st Session through the 2d Session of a Congress. Prior to the 97th Congress known as Executive (Lettered) Documents, and identified by letters of the alphabet
• Documents - (Senate & House)
  Contain various other materials ordered printed by both Houses of Congress. Documents can include reports of Executive Departments and Agencies, some of which are submitted in accordance with Federal law, then later are ordered printed as Documents. Sometimes Committee Prints are ordered printed as Documents also, if the information they contain is in demand. Documents have a larger distribution than Committee Prints.

Published in bound volumes from 15th Congress (1817-1819) through the 105th Congress (1995-1996), the US Congressional Serial Set sent to federal depository libraries (including Northwestern) became a victim of budget cuts in 1997. From that date the reports and documents that had been bound together into the Serial Set volumes continued to be received as individual publications by Northwestern University Libraries, and are available in print and digital format (see ProQuest and Readex databases linked below).  Other libraries may have purchased the bound Serial Set volumes published since 1997.

Both ProQuest and Readex provide digitized, searchable copies of the U. S. Congressional Serial Set volumes.  These are subscription databases and access is limited to currently affiliated faculty, staff, and students of Northwestern University.

Govinfo.gov provides free, open access to digitized copies of a wide range of federal government publications, including the U.S. Congressional Serial Set.