Professor Theoharis turned a advisor to the committee, which in 1975 and 1976 investigated the legality of the F.B.I., the C.I.A. and the National Security Agency’s intelligence operations. He did analysis within the archives of a number of presidential libraries, together with these of Truman, Eisenhower and Lyndon B. Johnson, on the categorized materials the F.B.I. despatched to presidents.
“They have access to F.B.I. records, unrestricted access,” he instructed Ms. Medsger and Ms. Hamilton, referring to the Church Committee and its counterpart within the House, led by Representative Otis Pike, a New York Democrat. “And it’s a different ballgame.”
And it was for Professor Theoharis as properly. He deployed FOIA, which had been strengthened by Congress in 1974, to plumb Hoover and his prime aides’ delicate “Official and Confidential” information, together with these designated “Do Not File,” which have been saved from the F.B.I.’s central data, presumably protected from being disclosed.
“That absurd “Do Not File’ file was one of the things that Athan drilled down on,” Professor Gage mentioned, “and he got a lot of information that way.”
Professor Theoharis wrote quite a few books in regards to the F.B.I., amongst them “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 reprinted company memorandums accompanied by Professor Theoharis’s commentary.
Reviewing “The Boss” in The New York Times, Herbert Mitgang wrote: “Unlike some other recent Hoover biographers, the authors do not make apologies for the excesses of ‘The Boss.’ They have the goods on him.”
Professor Theoharis thought that the portrait of Hoover as a gay cross-dresser that emerged in Anthony Summers’s 1993 book, “Official and Confidential: The Secret Life of J. Edgar Hoover,” was a distraction from the seriousness of Hoover’s unchecked authority.