By Bart Barnes Washington Post Staff Writer Thursday, August 15, 2002; Page B06 Meredith Knox Gardner, 89, an Army Signal Intelligence Service code breaker whose work on encrypted KGB messages to and from Moscow during and after World War II led to the exposure of Soviet agents who spied on the U.S. atomic bomb project, died Aug. 9 at the ManorCare facility in Chevy Chase. He had Alzheimer's disease. Mr. Gardner's work included the discovery of lists of code names in telegrams sent by the Soviet consulate in New York to Moscow from 1943 to 1945, and it led directly to the unmaskings of Klaus Fuchs, the German-born scientist convicted of spying for the Soviets; Julius and Ethel Rosenberg, who in 1953 were executed for espionage; and British intelligence officer Kim Philby, who after defecting to Moscow in 1963 said he had been a Soviet spy for two decades. Within the intelligence community, Mr. Gardner was said to have been a living legend, and his work in penetrating Soviet codes is widely considered one of the great U.S. counterintelligence coups of the last half-century. But he remained unknown to the public for more than 50 years until 1996, when he emerged from anonymity to tell his story at a conference on the decrypting operation, which had its own code name, "Venona." At that conference, which was sponsored by the National Security Agency, the CIA and the Center for Democracy -- a Washington think tank -- Sen. Daniel Patrick Moynihan (D-N.Y.) introduced Mr. Gardner as an unsung hero of the Cold War. Describing his discovery of code names in the New York to Moscow Soviet cables during and after the war, Mr. Gardner told the Venona conference: "That smelled of espionage. Otherwise, why would you go to the trouble of using something other than someone's real name?" In December 1946, his suspicions were all but confirmed when he decrypted a New York to Moscow cable sent two years earlier containing the code names of several leading scientists working on the Manhattan Project, the U.S. effort to build an atomic bomb. Mr. Gardner, a gifted linguist who was fluent in German, Old High German, Middle High German, Sanskrit, Latin, Greek, Lithuanian, Slavonic, Spanish, French, Italian, Russian and Japanese, came to Washington early in World War II to work as a civilian for the Army Signal Intelligence Service, a predecessor of the NSA. A native of Okolona, Miss., he graduated from the University of Texas and received a master's degree in languages from the University of Wisconsin. Before World War II, he was a language teacher at the Universities of Akron, Texas and Wisconsin. He spent his early years with the Army agency working on telegraphic messages involving Germany and Japan, especially communications between Japanese military attaches in Berlin and other enemy capitals and the Japanese general staff in Tokyo. When the war ended, Mr. Gardner was reassigned to examine telegraphic traffic involving the Soviet Union, the wartime ally of the United States and Great Britain. With the end of hostilities against Germany and Japan, Soviet matters were now a top priority, and by 1946 from 500 to 600 people were assigned to decryption efforts on more than 35,000 pages of coded Soviet cables. As senior linguist, it was Mr. Gardner's job to re-create a Russian code book and translate Russian messages into English. He told The Washington Post's Michael Dobbs in 1996 that he attributed his success to logic, his linguistic skills and "a sort of magpie attitude to facts, the habit of storing things away that did not seem to have any connection at all." A few months after decoding the message containing the names of scientists working on the atomic bomb, he came upon a reference to an agent with the code name of "Liberal" who had a 29-year-old wife named Ethel. They turned out to be Julius and Ethel Rosenberg. As more Venona cables were decrypted, it became apparent that Moscow had recruited dozens of agents at various levels of government, and the FBI was directed to follow up leads. Robert Lamphere was the FBI agent named liaison officer with Venona, and with Mr. Gardner he developed a symbiotic relationship in which Mr. Gardner gave Lamphere lists of agents named in the Venona cables while Lamphere gave Mr. Gardner information that might be helpful in further decryption. This led to a massive manhunt for spies in the late 1940s and early 1950s and is said to have contributed to the Communist-baiting excesses of Sen. Joseph McCarthy (R-Wis.). Among the other Soviet agents mentioned in the Venona documents were David Greenglass, the younger brother of Ethel Rosenberg who received a 15-year prison sentence for passing along information about the atomic bomb; and Theodore Alvin Hall, who was recruited as a 19-year-old Harvard student to work on the bomb and was then said to have passed along the vital secrets of this work to the Soviets. Hall was never formally charged. He died in Cambridge, England, in 1999. Information from the Venona operation also led to the exposure of Kim Philby's British comrades in espionage, Guy Burgess, Donald Maclean and Anthony Blunt. From at least two sources, the Soviets learned that their U.S. espionage net had been discovered. One was Philby, the British intelligence officer and double agent. He was posted in Washington in 1949 and had a habit of dropping in on Mr. Gardner's Venona operation. The other was Bill Weisband, a Russian emigre who was hired as a linguistic adviser for Venona. Mr. Gardner occasionally consulted him on points of Russian grammar. At the Venona conference, the National Security Agency declassified tapes of the confession of a Los Angeles aircraft worker who identified Weisband as his KGB handler. Weisband was fired from Venona and later served a one-year prison sentence for contempt of court for refusing to testify about Communist connections. He died in 1967. U.S. counterintelligence officials said they are convinced he was a Soviet spy. In 1972, Mr. Gardner retired from NSA. The Venona operation was shut down in 1980. In retirement, Mr. Gardner lived quietly in a modest condominium on Connecticut Avenue in Washington, where he traced his Scottish genealogy and did the daily crossword puzzle in the Times of London, which is reputed to be the most difficult in the world. Survivors include his wife of 57 years, Blanche, of Washington; two children, Arthur H. Gardner of Milwaukee and Ann Martin of Annapolis; and 11 grandchildren. � 2002 The Washington Post Company