The Soviet KGB mounted a massive bugging operation in the United States in the 1970s and early '80s that provided the Kremlin with intelligence on everything from Henry Kissinger's phone conversations to top-secret weapons, according to revelations by a Soviet defector.

Intelligence experts have long acknowledged that the Soviet Union excelled in the field of human intelligence, or Humint, as demonstrated by its ability to recruit hundreds of informers in the United States for either ideological or mercenary motives. It now turns out that the KGB scored important successes in signals intelligence, or Sigint, an area in which the United States has long been regarded as superior.

A new book drawing on notes smuggled out of Russia by a former KGB archivist asserts that the Soviet missions in Washington and New York were the hub of the eavesdropping operation. One KGB document cited by the defector, Vasili Mitrokhin, claimed that more than half the projects of the Soviet defense industry in 1979 were based on intelligence from the West.

Mitrokhin, who defected to Britain in 1992 after being turned away by the CIA, took detailed notes on some of the KGB's most highly classified files over a 12-year period prior to his retirement in 1984. He smuggled the notes out of the KGB headquarters in his shoes and pockets, and buried them under the floorboards of his dacha, or country home.

"As a source of details and data about Soviet intelligence operations, this is an absolutely unprecedented gold mine," said Paul Redmond, former head of counterintelligence for the CIA. Redmond said he was particularly struck by the "breadth and boldness" of the KGB's technical operations in the United States.

"When you take the mother lode of information provided by Mitrokhin, and couple it with other sources, you get a very strong, cynical, immoral and evil picture of KGB activities in the West," said John L. Martin, former chief of the internal security section of the Department of Justice, who used Mitrokhin's information to build an espionage case against a former National Security Agency employee, Robert Lipka, who was sentenced to 18 years' imprisonment in 1997.

Other revelations in "The Sword and the Shield" (Basic Books) by Mitrokhin and his British co-author, Christopher Andrew, include:

* The KGB sought to link the CIA to the assassination of President John F. Kennedy by forging a letter from Lee Harvey Oswald to a CIA officer, E. Howard Hunt. The letter, which indicated that Oswald wanted to meet Hunt before going ahead with the killing, was fabricated in the mid-'70s after Hunt's name appeared in the press in connection with the Watergate scandal.

* The KGB planned to sabotage the Flathead dam in Montana, the port of New York, and the power supplies of New York state, among other targets. Based on Mitrokhin's information, a booby-trapped arms cache was recently discovered and destroyed in Switzerland, and the authors believe that similar arms caches could be scattered across the United States.

* The KGB spread disinformation in an attempt to discredit prominent American figures, including former national security adviser Zbigniew Brzezinski, former FBI director J. Edgar Hoover and civil rights leader Martin Luther King Jr. One KGB plan called for planting a bomb in a black neighborhood of New York to be followed by anonymous calls blaming the explosion on the Jewish Defense League.

Many of these plans either fell flat or were never carried out. But the KGB did succeed in intercepting the fax communications of U.S. defense contractors, including Boeing, General Dynamics, Hughes, IBM and Lockheed. According to Mitrokhin's documents, the intercepts provided important material on the Trident, MX and Pershing missile systems; the F-15, F-16 and B-1 aircraft; and the AWACS radar system.

The KGB was particularly proud of a bugging operation against System Planning Corp., a defense contractor in Arlington, that yielded "highly important" information on U.S. nuclear weapons in Europe, chemical weapons, laser guidance systems and the Navy's chances of surviving a nuclear conflict.

Under the operation, codenamed FLAMINGO, a Soviet diplomat, Viktor Lozenko, planted a listening device under a table in the company's conference room during an unclassified meeting. The same 15th-floor conference room was later used by Pentagon officials for classified meetings. Soviet agents were able to listen in to the secret meetings from a car with diplomatic license plates stationed a quarter-mile away.

System Planning's vice president for advanced technology, Tucker Battle, yesterday expressed surprise at the espionage allegations, saying the conference room was routinely swept for listening devices before classified meetings. But he confirmed that the room was occasionally used for nonclassified discussions by the Washington Operations Research Council, to which Soviet diplomats might have been invited.

Operating out of the Soviet Embassy on 16th Street NW, KGB agents also succeeded in intercepting messages between Andrews Air Force Base and government aircraft used by the president, the secretary of state and other senior officials. According to Oleg Kalugin, a former KGB agent in Washington, KGB chief Yuri Andropov "loved" listening to intercepted conversations between Kissinger and his then-fiancee, Nancy Maginnes.

The KGB disinformation campaigns appear to have been less effective. One such campaign involved an attempt to discredit Brzezinski, a Catholic of Polish descent, by depicting him as Jewish and hinting at an affair with actress Candice Bergen. "It makes you wonder how stupid the KGB are," says Brzezinski, who cannot remember ever meeting Bergen. "I think I could have done a better job compromising myself."

CAPTION: The KGB reportedly sought to link the CIA to the assassination of John F. Kennedy by forging a letter from Lee Harvey Oswald, left, to E. Howard Hunt.