The FBI has finally agreed to make public the final 10 documents about the surveillance of John Lennon that it had withheld for 25 years from a University of California, Irvine, historian on the grounds that releasing them could cause "military retaliation against the United States."

Despite the fierce battle the government waged to keep the documents secret, the files released Tuesday contain information that is hardly shocking, just new details about Lennon's ties to New Left leaders and antiwar groups in London in the early 1970s, said the historian, Jon Wiener.

For example, in one memo, then-FBI Director J. Edgar Hoover wrote to H.R. Haldeman, President Nixon's chief aide, that "Lennon had taken an interest in 'extreme left-wing activities in Britain' and is known to be a sympathizer of Trotskyist communists in England."

Another document that had been totally blacked out on the grounds of national security when Wiener obtained it more than 20 years ago through litigation brought under the Freedom of Information Act, said that two prominent British leftists, Tariq Ali and Robin Blackburn, had courted Mr. Lennon in hopes that he would "finance a left-wing bookshop and reading room in London."

But the newly released document adds, that Mr. Lennon apparently gave them no money "despite a long courtship by Blackburn and Ali."

Rather, the previously classified document states that Mr. Lennon was using his "tangible assets" to try to get custody of his wife Yoko Ono's child, who was in the care of her former husband.

Another surveillance report states explicitly that there was "no certain proof" that Mr. Lennon had provided money "for subversive purposes," and yet another states that there was no evidence that Mr. Lennon had any formal tie to any leftist group. Only one document alludes to Mr. Lennon's music, saying he has "encouraged the belief that he holds revolutionary views ... by the content of some of his songs."

Still another describes an interview with Mr. Lennon published in the 1971 in an underground London newspaper called the Red Mole. "Lennon emphasized his proletarian background and his sympathy with the oppressed and underprivileged people of Britain and the world," the document states. Another said he had signed an appeal supporting Cambodian Prince Nordom Sihanouk, who was neutral at the time the U.S. invaded Cambodia.

Mr. Wiener and his attorneys, Dan Marmalefsky of Morrison & Forster and Mark Rosenbaum of the American Civil Liberties Union of Southern California, all said the documents revealed that there was no sign that government officials considered Mr. Lennon a serious threat. They expressed mystification that several administrations had for so long resisted making the material public.

"The content of the files released today is an embarrassment to the U.S. government," said Mr. Wiener, 62, who has written two books on the late Beatle, "Come Together: John Lennon in His Life," and "Gimme Some Truth."

"I doubt that Tony Blair's government will launch a military strike on the U.S. in retaliation for the release of these documents. Today, we can see that the national security claims that the FBI has been making for 25 years were absurd from the beginning," said Mr. Wiener, who first requested the documents in 1981.

Mr. Wiener initially obtained some documents showing that the FBI closely monitored Mr. Lennon's activities in 1971 and 1972. The documents indicated that the Nixon administration was concerned that Mr. Lennon would support then-Sen. George S. McGovern, D-S.D., for president against Mr. Nixon in 1972, the first year that 18-year-olds could vote. The files also revealed that government officials worried that Mr. Lennon might participate in protests at the Republican National Convention.

But the FBI also withheld numerous files, saying that they were exempt from the Freedom of Information Act, including part of a surveillance report on a December 1971 antiwar rock concert and rally in Ann Arbor, Mich., where Mr. Lennon urged that activist and singer John Sinclair be released from prison. Mr. Sinclair was being held on a 10-year sentence for possession of two joints of marijuana. A judge soon freed Mr. Sinclair.

Mr. Wiener sued in U.S. District Court in Los Angeles seeking all the documents. The FBI countered that some of the documents contained "national security information provided by a foreign government under an explicit promise of confidentiality," and that release of the documents "can reasonably be expected to ... lead to foreign diplomatic, economic and military retaliation against the United States," according to a government legal brief filed in 1983.

Mr. Wiener lost the initial court skirmishes, but in 1991 he won a major victory in the 9th U.S. Circuit Court of Appeals, which ruled that declarations filed by FBI agents provided inadequate grounds for keeping the material secret. From that point forward, the court ruled, the FBI had to file "affidavits containing sufficient detail" to allow Mr. Wiener to "intelligently advocate" for their release and for a trial judge "to intelligently judge the contest."

That decision significantly strengthened the hand of people trying to pry secret documents out of the government. Justice Department attorneys, including John Roberts, who is now the chief justice, appealed, but the Supreme Court let the ruling stand.