Professor Theoharis became an advisor to the committee that investigated the legality of the intelligence operations of the FBI, the CIA and the National Security Agency in 1975 and 1976. He researched the archives of several presidential libraries, including those of Truman, Eisenhower, and Lyndon B. Johnson, over the secret material the FBI sent to presidents.
“You have access to FBI records, unrestricted access,” he told Ms. Medsger and Ms. Hamilton, referring to the church committee and its counterpart in the House of Representatives, led by Rep. Otis Pike, a New York Democrat. “And it’s a different ball game.”
And it was for Professor Theoharis too. He used FOIA, which was strengthened by Congress in 1974, to explore the sensitive “official and confidential” files of Hoover and his top staff, along with those labeled “Do Not File” extracted from the central FBI records, presumably safe, were kept from disclosure.
“That absurd ‘Do Not File’ file was one of the things that Athan investigated,” said Professor Gage, “and he obtained a lot of information that way.”
Professor Theoharis wrote numerous books on the FBI, including “The Boss: J. Edgar Hoover and the American Inquisition” (1988, with John Stuart Cox) and “From the Secret Files of J. Edgar Hoover” (1991), which were reprinted Agency memoranda accompanied by a comment from Professor Theoharis.
In a review of “The Boss” in the New York Times, Herbert Mitgang wrote: “Unlike some other recent Hoover biographers, the authors do not apologize for the excesses of ‘The Boss’. You have the goods with you. “
Professor Theoharis thought that the portrait of Hoover as a homosexual crossdresser that appeared in Anthony Summers’ 1993 book, Official and Confidential: The Secret Life of J. Edgar Hoover, was a distraction from the seriousness of Hoover’s unchecked authority.