One of the harder to find classes of government documents are declassified documents. In many cases these are not within the scope of the Federal Depository Library Program, so there isn't a centralized place to find them. Sometimes they're not actual publications, but stuff like memos, celebrity FBI files and the like. If you're researching public policy, especially national security, stuff that might be helpful might be declassified or subject to declassification under the Freedom of Information Act (FOIA). But before you start filing that FOIA request, check out today's Guide of the Week [1] from the ALA GODORT Handout Exchange [2], because what you want might already be out there:

Declassified Government Documents [3] (UC-Berkeley, 2004) CC Last updated 9/15/2006

I really like how this guide starts out. Because the Berkeley librarians understand that declassified documents are a misty topic to most people, they start with an introduction:

About Declassified Documents

Documents may be classified for many reasons - issues of national security or privacy. A popular misconception is that when a document is declassified, it is somehow systematically made available to the public, for example, distributed to depository libraries. This is most often not the case. Exceptions to this might be

• a highly-publicized document is published as a part of an investigation. E.g. The Munson Report, a report from the fall of 1941 stemming from an intelligence gathering investigation on the loyalty of Japanese Americans is one of these exceptions. It was declassified and published as one of the many appendices in the Hearings held by the Joint Committee on the Investigation of the Pearl Harbor Attack in 1946.
• a document series that is specifically published by the government for researchers (e.g. Foreign Relations of the U.S. or the Library of Congress Presidential Papers collections).

As there are no clear patterns of publication for most declassified documents, it falls to the researcher interested in a document that is declassified to research which agency created the document, who may have researched the document originally, and where it might be now. The guides and resources shown below are intended to assist the research in finding federal records that have been declassified as part of the routine declassification, as well as records that are declassified through FOIA (Freedom of Information Act) requests and other kinds of investigations.

After this intro, they have additional material about the declassification process and FOIA. Then they talk about resources including:

• The encyclopedia of American intelligence and espionage : from the Revolutionary War to the present [4]. G.J.A. O'Toole. New York : Facts on File, c1988.
  UB271.U5 O85 1988 GREF
  References individuals, committees, and operations. Many of the entries have footnotes.

• Unlocking the files of the FBI : a guide to its records and classification system [5] by Gerald K. Haines and David A. Langbart. Wilmington, Del. : Scholarly Resources, 1993. HV8144.F43 H35 1993 GREF
• OpenNet via Department of Energy [6]
  OpenNet includes references to all documents declassified and made publicly available after October 1, 1994. New references are added periodically as they occur. These collections include citations to several types of documents. Some have been declassified in total, and are termed "declassified." Others have had classified or other restricted information removed to produce a "sanitized" copy. The term "redacted" is sometimes used to refer to these documents.

There are a lot more. See http://www.lib.berkeley.edu/doemoff/govinfo/federal/gov_decldoc.html [7] for details. Then check out what other subject guides [8] are available. And if you're a docs librarian with a handout of your own, link it to the wiki!.