Joel Barr, also Iozef Veniaminovich Berg and Joseph Berg, was born in 1916 to Jewish immigrant parents. He attended City College of New York (CUNY) with Julius Rosenberg and later worked with Rosenberg and Al Sarant at the United States United States Army Signal Corps laboratories at Fort Monmouth, New Jersey during World War II. Barr and Sarant, who were recruited into espionage by Rosenberg, shared an apartment and were allowed to function as a team by their KGB Case Officer, Aleksandr Feklisov. Feklisov regarded the pair as the most productive members of the group. Harry Gold, besides Rosenberg, sometimes also couriered information to and from Barr and Sarant.
Both Barr and Sarant were trained and employed as electrical engineers and worked on military radar. Barr was discovered by counterintelligence to be a Communist and was fired. He and Sarant then found employment with Western Electric and worked on a highly secret radar bombsight.
When the war ended the two founded Sarant Laboratories, and sought defense contracts, but the company soon failed, after which the two split up. Barr worked for a while in late 1946 with Sperry Gyroscope Company on secret military radar systems, but was fired in 1947 after the United States Air Force refused him a security clearance. Barr then moved to Paris and continued graduate engineering studies.
After the arrest of Klaus Fuchs in early 1950, Barr and Sarant where named by Fuchs as Soviet operatives. Harry Gold was arrested in May 1950, and David Greenglass in June. Barr suddenly disappeared from his Paris apartment and fled to Czechoslovakia without taking his belongings, and from there to Moscow where he remained out of sight for more than thirty years. In Moscow, Barr eventually met up with Sarant and a woman Sarant ran away with. The two were given new identities and resettled in Czechoslovakia as electronics engineers. Barr assumed the identity of Joseph Berg, and claimed to have South African origins.
In 1956 the two transferred to Leningrad and were put at the head of a military electronics research institute, and enjoyed the benefits of the Soviet Nomenklatura. The two were credited with founding the Soviet microelectronics industry. Barr claimed they created the first Soviet radar-guided anti-aircraft artillery and surface-to-air missiles, weapons that proved highly effective against American aircraft in the Vietnam War.
In 1983, a Russian émigré, Mark Kuchment, working at Harvard University's Russian Research Center, who had read The Rosenberg File, linked Barr and Sarant to two prominent Soviet scientists, both native speakers of English.
After the collapse of the Soviet Union in 1992, Barr returned to the United States but denied his participation in espionage. He died in 1998 in St. Petersburg, Russia.
There are seven deciphered KGB transmissions about Joel Barr. Barr's code name in the Soviet intelligence and in deciphered Venona project transcripts was originally "Meter" (also "Metre" and "Metr"); it was later changed to "Scout" (also "Skaut"). The November 14, 1944 Venona cable also documents the successful recruitment of Ruth Greenglass.
- John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America (New Haven: Yale University Press, 1999)
- Allen Weinstein and Alexander Vassiliev, The Haunted Wood: Soviet Espionage in America—the Stalin Era (New York: Random House, 1999)
- Feklisov, Alexandre, The Man Behind the Rosenbergs: Memoirs of the KGB Spymaster Who Also Controlled Klaus Fuchs and Helped Resolve the Cuban Missile Crisis, (New York,Enigma, 2001)
- FBI Venona file
- Making it in the USSR, By Mark Kuchment
- PBS Nova Online, The November 14, 1944 cable: Joel Barr and Alfred Sarant
- Ronald Radosh and Joyce Milton, The Rosenberg File: A Search for the Truth, Henry Holt (1983), hardcover, ISBN 0030490367
- Steven T. Usdin, Engineering Communism: How Two Americans Spied for Stalin And Founded the Soviet Silicon Valley, Yale University Press (October 10, 2005), hardcover, ISBN 0300108745