Ethel Greenglass was born in New York on 28th September, 1915. She attended the Seward High School with her brother, David Greenglass. After taking a short secretarial course, she held a variety of clerical jobs and became an active trade unionist.
In 1939 Ethel married Julius Rosenberg. During the Second World War Julius was employed as a civilian inspector for the Army Signal Corps, but was dismissed in 1945 as a result of allegations that he was a member of the American Communist Party. Rosenberg now opened a small machine shop in Manhattan with Ethel's brother, David Greenglass. However, the business did badly and Greenglass left the partnership.
On 5th September 1945, Igor Gouzenko, a KGB intelligence officer based in Canada, defected to the West claiming he had evidence of an Soviet spy ring based in Britain. Gouzenko provided evidence that led to the arrest of 22 local agents and 15 Soviet spies in Canada. Some of this information from Gouzenko resulted in Klaus Fuchs being interviewed by MI5. In 1950 Fuchs, head of the physics department of the British nuclear research centre at Harwell, was arrested and charged with espionage. Fuchs confessed that he had been passing information to the Soviet Union since working on the Manhattan Project during the Second World War. However, after repeated interviews with Jim Skardon he eventually confessed on 23rd January 1950 to