They are known as the "family jewels" -- documents so secret, and so potentially damaging, that the CIA has fought to keep them classified until now.
In 1973, then-CIA-director James Schlesinger ordered the 700-page dossier that compiled decades of illegal activities by the agency.
"In effect, the family jewels are a series of CIA officers going into the confessional and saying, 'Forgive me father, for I have sinned,'" said Tom Blanton, director of the National Security Archive at George Washington University.
Many details were later revealed in newspaper reports and Congressional hearings.
It is the stuff of spy novels. The abuses include assassination conspiracies against foreign leaders like Fidel Castro, the infiltration of anti-war groups, and the screening of private mail -- including letters to actress and anti-war activist Jane Fonda.
The CIA also put journalists under surveillance, including columnist Jack Anderson and his then-assistant Brit Hume.
Former Washington Post reporter Michael Getler was monitored by a team of agents around the clock. He found out about the surveillance from a front-page story in the Post.
"They were watching who I was talking to," he said. "They took pictures of who I was having lunch with. They actually took pictures though the picture window of our home. ... It was very spooky, very spooky. I mean, this is America and you don't expect that."
The CIA would have had to release the documents eventually under the Freedom of Information Act. But the decision to do it now may reflect a new openness on the part of the agency about its cloak-and-dagger past.
CIA Director Michael Hayden recently described the documents as "a glimpse of a very different time and a very different agency."
But this all comes when the CIA is under fire for an alleged array of current abuses, including the use of secret prisons and torture. Some say the activities of the past may look mild by comparison.
"A lot of the things that were done in a very mild degree back in the '50s, '60s and '70s are now being done on a wholesale basis," said author and national security expert James Bamford.