WASHINGTON -- The CIA has released 19,000 pages of classified intelligence briefings that took place during some of the darkest days of the 1960s.

It was President Kennedy, angered by bad intelligence on the disastrous attempted invasion of Cuba's Bay of Pigs, who first asked for a daily rundown of the latest top secret intelligence.

"They called it 'The Pickle,' short for the president's intelligence checklist," CIA Director John Brennan said.

The first version in 1961 was written to fit in the president's breast pocket and stamped "Top Secret."

The following year, after the Soviets pulled back their missiles in Cuba, the CIA said, "We see Khrushchev's Cuban missile misadventure as a major setback for him personally," and noted Fidel Castro's displeasure.

Three days after President Kennedy was assassinated, the daily briefing confirmed that Lee Harvey Oswald had been in Mexico.

"He was trying, we are told, to arrange for visas so that he could travel to the USSR via Havana," the briefing said.

Lyndon Johnson didn't like the "Pickle" style briefing -- perhaps because Kennedy had never allowed him to read it. The CIA tailored a new one for him -- titled "The President's Daily Brief." And they changed the delivery schedule.

"And they delivered it in the afternoon, not the morning, since Johnson liked to do his reading at the end of the day, often in his pajamas while lying in bed," Brennan said.

In the years to come, the war in Vietnam consumed LBJ. In 1967, he asked for a daily supplement on the war, "For the President's Eyes Only."

After the 1968 Tet Offensive, CIA briefers reported that North Vietnamese broadcasts boasted of hundreds dead in the attack on the U.S. Embassy when, in fact, no one had died. President Johnson, claimed the Vietnamese, "could not eat and sleep properly." He was confused "as the man in the moon."

The briefings have continued through every president since JFK, filled with gossip and guesses as well has hard facts. A later CIA director called them the agency's "most important product." But the delivery has changed. These days, President Obama gets his top secret fix on an electronic tablet.