BOB GARFIELD: From WNYC in New York, this is NPR's On the Media. I'm Bob Garfield.

BROOKE GLADSTONE: And I'm Brooke Gladstone. This week's revelation in The New York Times marked an escalation in the ongoing struggle over government secrecy. It reported that more than 55,000 pages of declassified documents, stretching back decades, had simply disappeared from public view, reclassified, despite the fact that many of the documents had been, for years, publicly accessible, copied and widely disseminated. The reclassification of these documents is in some ways the latest pull in a tug of war that began when then-President Clinton signed a 1995 executive order expediting the release of massive amounts of Cold War, Pentagon and intelligence agency documents. Matthew Aid is the historian who inadvertently discovered the missing documents and the program that disappeared them. He joins us now. Matthew, welcome to the show.

MATTHEW AID: Great to be here. Thank you.

BROOKE GLADSTONE: So how did you discover that these documents were missing?

MATTHEW AID: Purely by accident. While doing research for my book, I submitted a request to see some State Department documents, which I had examined some nine years ago, and got the response back that the documents had been withdrawn from the public record in late 1999. I basically interrogated a series of National Archives staff members and asked them why the documents had been withdrawn. Most were very reluctant to say anything at all because evidently there was an order not to speak to researchers about the subject. Finally, I found an archivist who was frustrated and very brave, and told me the whole story.

BROOKE GLADSTONE: Do you have a sense of generally the kind of documents that have been removed?

MATTHEW AID: I do. Most of the documents that had been removed were in the form of memos and reports that generally tended to be very critical of the Pentagon and the CIA's performance, but were very mundane and very dull. The documents they're pulling relate, for example, to the budget for the State Department Intelligence Office for the years 1948-49.

BROOKE GLADSTONE: [LAUGHS]

MATTHEW AID: They're classifying documents relating to assessments of Guatemalan agrarian reform in 1951.

BROOKE GLADSTONE: Along with a bunch of documents that were really right for declassification, there were some that you say should never have been declassified; that they were downright scary. So perhaps this entire program was an overreaction to a very real problem.

MATTHEW AID: There are, for example, in the records of the predecessor to the CIA, the Office of Strategic Services, assassination manuals. There are manuals on how to construct high explosive devices from garden-variety materials. There are also, in a variety of records, which, by the way, the CIA and the Pentagon have not even looked in, very technical documents relating to the biological weapons development programs that we were engaged in, in the late 1940s and 1950s. I understand enough from my university biology class to know that these things probably should not be on the public shelves. These documents were declassified in the 1980s and have remained on the public shelves now for going on 30 years.

BROOKE GLADSTONE: And yet, you're saying these are precisely the documents that they haven't gone through. Instead, they're going through documents that really don't seem to pose any national security risk at all.

MATTHEW AID: That's absolutely correct.

BROOKE GLADSTONE: Now, there is an oversight body for changes in classification. It's called the Information Security Oversight Office. It wasn't notified in this case, and the explanation is that these documents were not actually declassified to begin with, even though they were stamped "declassified" and reviewed before putting on the shelf. So if they were never declassified, then nobody needs to be told that they're un-declassified.

MATTHEW AID: It is almost Dali-esque.

BROOKE GLADSTONE: [LAUGHS]

MATTHEW AID: Now, the fact that the government has said that they were inadvertently released is a legalism which allows them to get around the strictures of the executive order signed by President Clinton and amended by President Bush in 2003, which requires any agency engaging in reclassification work to formally and in writing notify the Information Security Oversight Office that they had made that decision. They did not.

BROOKE GLADSTONE: You know, Matthew, I'm wondering -- The New York Times piece that broke on Monday made reference to 30 reviewers, contractors for the Defense and the intelligence agencies poring every weekday over these documents and deciding which to reclassify in a custom-built, one-million-dollar room. How did this kind of effort go unnoticed?

MATTHEW AID: I think this is a question that Congress should be asking. As best as I can tell, talking with friends of mine on Capitol Hill, this entire effort has been funded through back channels. It has never been formally approved by any Congressional committee that my friends are aware of. There are going to be hearings held by Congressman Chris Shays of Connecticut in three weeks time, and this is probably one of the questions that is going to get asked, if not by the members of the committee, certainly by myself and other interested members of the public.

BROOKE GLADSTONE: What can you do, as a historian, besides testify? Could you gum up the works with a bunch of Freedom of Information requests?

MATTHEW AID: That's one possibility. I could file four-year requests for each and every one of the 55,000 pages of documents that have been reclassified and drown [LAUGHS] the agencies in paperwork. I think, more practically, what I think should happen is that Bill Leonard's Information Security Oversight Office should continue the audit that it's conducting right now of all the documents that have been reclassified. Hopefully, we'll manage to terminate this program and send the security screeners off to do something more meaningful with their lives.

BROOKE GLADSTONE: What do you think the real stakes are here?

MATTHEW AID: A lot of this is multiple government agencies that have been struggling with each other over the whole issue of declassification. By the time these people are finished, they could potentially remove several hundred thousand pages of documents. The kinds of documents they're taking out are those that do not necessarily reflect well on those agencies, and, I think, as a result, they're warping history.

BROOKE GLADSTONE: Matthew Aid, thank you very much.

MATTHEW AID: My pleasure. Thank you for having me.

BROOKE GLADSTONE: Matthew Aid is an independent intelligence historian and recently completed the first volume of a multi-volume history of the National Security Agency. [MUSIC UP AND UNDER]