For 10 years at the peak of the cold war, he served as the chief of West Germany's espionage activities against the Soviet Bloc. But his true employers sat in KGB headquarters in Moscow, and he loyally fed them the most precious information that crossed his desk.

The saga of Heinz Felfe, one of the most proficient known Soviet agents to pass through the looking glass of the East-West intelligence war, is never distant from the minds of western spy chiefs when they ponder Bonn's vulnerability to infiltrators and consider how much sensitive material they can share with their West German allies.

Twenty-five years after his arrest in West Germany for high treason, Felfe emerged today from his sheltered life as a former Soviet Bloc agent to launch the publication of his autobiography, "In Service of the Adversary." In his solemn blue suit, gray hair and thick eyeglasses, he looked more like a professor than a double agent who inflicted some of the worst damage to western intelligence at a critical stage in postwar history.

"I am satisfied with my life," he declared at a press conference in one of East Berlin's plushest hotels. "I have lived my life and made a contribution to society as I understand it. I am happy here, and I still get my pension from the KGB."

The rare spectacle of a Soviet agent hawking his memoirs stirred speculation among diplomats and other foreign analysts that apart from disseminating Soviet-approved perspectives through a Hamburg publishing house, Moscow's intelligence elite wanted to signal its foreign agents that a pleasant retirement warranted the risks of a jail sentence in the West.

Felfe said he was allowed to conduct research for his book in KGB archives in Moscow, where he says he was able "to read all that my own hand had put there." He contended that his "KGB friends" said he could write what he wished and that he deleted upon their request only a few incidents.

"I have my Mercedes and my video recorder; I am very comfortable," Felfe added later, as he signed copies of his book. Asked about his family, he said he was divorced, then lowered his eyes and mentioned that his children remain in West Germany and do not wish to speak to him.

Felfe was released in 1969 as part of a major East-West spy swap after serving six years of a 15-year sentence. He settled in East Berlin and was named professor of criminology at Humboldt University.

In his press conference, Felfe sketched an extraordinary spying career that evolved from his wartime service as a SS criminal officer and his recruitment, as a prisoner of war, by Soviet intelligence officers in the ruins of Berlin.

He said he developed strong sympathies with the Soviet cause and accepted the delicate task of penetrating West German intelligence services being set up under supervision of the U.S. intelligence.

"It was absolutely clear to me that the hope for the future lay with the Soviet Union and not in the United States," Felfe said. He said he became disgusted with the western allies because of the carpet-bombing raids that destroyed his native city of Dresden.

During his tenure as head of West German intelligence activities targeted on the Soviet Union, Felfe was able to supply Moscow with what Bonn government officials admitted was some of the most highly classified information exchanged at that time between West Germany and its allies.

Felfe's work for Moscow reportedly compromised even the basic structure and techniques utilized by West German intelligence, which was thoroughly revamped after his exposure as a double agent.

His treason, according to his former West German intelligence boss, Reinhard Gehlen, also led to the arrest and deaths of many agents during the 1950s. But Felfe refused to confess to any guilt, saying that his colleagues harbored political opinions that he could not share.

In response to questions by western reporters, Felfe said he has not yet met Hans-Joachim Tiedge, the West German counterintelligence officer who defected to the East last year amid mounting personal problems with debts and alcoholism.