But no historical account shows that Bissell, who ran the project, ever told Dulles. Or that either man told Kennedy when he got his first in-depth national intelligence briefing on the Cuba crisis on Nov. 18 -- by the swimming pool at the Kennedy family's Palm Beach vacation home.

''If they thought it was unachievable, one could argue that Bissell owed it to JFK to tell him what they thought. There is no evidence that he did,'' said Barrett, who found the document while researching his latest book, The CIA and Congress: The Untold Story From Truman to Kennedy.

'COMPLETE AND FRANK'

Bissell didn't report what he told Kennedy in his own memoirs, published in 1996, two years after the once-celebrated spy master died.

''The presentation took less than an hour and was complete and frank,'' Bissell wrote in Reflections of a Cold Warrior.

''When the session ended, I drifted off to another part of the terrace while Kennedy and Dulles transacted other business.''

Says former Herald Latin America editor Don Bohning, author of The Castro Obsession, who read the Pfeiffer report, too: ''Bissell seems to have had a habit of not telling people things they needed to know.''

Historians had thought that Pfeiffer's full four-volume CIA history, Official History of the Bay of Pigs Operation,was still classified.

But Volume Three, called Evolution of CIA's Anti-Castro Policies, 1951-January 1961,arrived at the National Archives Kennedy Assassinations collection with just a few deletions of classified information in 1998 or 1999. Bay of Pigs scholars have only read it in recent weeks, after Barrett announced its existence by posting it on his university web page.

'A TREASURE TROVE'

And, said Kornbluh, whose National Security Archives has for years sifted through classified documents about long-hidden Latin American missions, Pfeiffer provided ''a treasure trove of detail on one of the most significant covert actions and foreign policy debacles in the history of the Cold War.''

It described how the Bay of Pigs invasion morphed: from a plan to drop a small, U.S.-trained Cuban guerrilla force onto the island to incite internal rebellion into the full-blown, externally directed U.S.-Cuban exile assault.

Kornbluh added that the WH/4 analysis was so sound that it eerily foreshadowed a scathing and sometimes controversial report written by CIA Inspector General Lyman Kirkpatrick in the summer of 1961.

ARROGANCE BLAMED

Kirkpatrick blamed the Bay of Pigs fiasco on institutional arrogance, ignorance and incompetence, saying a major paramilitary operation of this type was ''beyond agency responsibility and capability.''

Written on a typewriter in the 1970s, Pfeiffer dryly documented the earliest Cold War brainstorming sessions on how to overthrow Castro -- long before the Kennedy-era team hatched the better-known plots of Operation Mongoose.

Pfeiffer called them ''wild-haired proposals.''

The CIA report also shows early Eisenhower administration contact with big business on anti-Castro operations.

It highlights the role of Republican Miami businessman William Pawley, a former U.S. ambassador in Latin America, who supported Richard Nixon's presidential bid and hosted meetings between the intelligence agency and U.S. business.

The topic: The composition of a post-Castro, U.S.-backed Cuban government.

MET WITH FIRMS' EXECS

And on Dec. 20, 1960, Pfeiffer said, Dulles met U.S. corporate leaders in New York to kick around ideas for covert operations at a particularly delicate time -- during the transition from President Eisenhower to Kennedy.

Executives included the Cuban-American Sugar Co. chairman, the American Sugar Domino Refining Co. president, the president of the American and Foreign Power Co., Standard Oil of New Jersey's vice president for Latin America, representatives of Texaco, International Telephone and Telegraph ''and other American companies with business interests in Cuba.''

VARIED IDEAS

''Suggestions were made to sabotage the sugar crop -- the question being whether to burn the cane fields or ruin the refineries; to interrupt the electric power supply; and to put an embargo on food, drugs and spare parts for machinery,'' Pfeiffer wrote, quoting from a memorandum from the meeting written by Henry Holland, a former assistant secretary of state for inter-American affairs.

''Dulles opposed the embargo on food and drugs, but the feeling of the business group was that it was time to get tough and, hopefully, the blame for an embargo would be laid on Castro.''