Margaret Gowing, née Elliott, was born in London, the youngest of three children in an impoverished family. In 1932, she won a scholarship to Christ's Hospital School, where she excelled academically, then won a scholarship to the London School of Economics. There she won both the Gladstone Memorial Prize and the Lillian Knowles Scholarship for economic history in 1939. She graduated in 1941 with a BSc degree in economic history with first-class honors. As it was difficult for women to find academic jobs at that time, she joined the British Civil Service, working in the Ministry of Supply. She subsequently moved to the Board of Trade, and the Directorate of Housing Fitments, where she rose to the rank of Assistant Principal, before moving to the historical section of the Cabinet Office in 1945. In 1944, she married Donald Gowing, with whom she had two sons. Over the next 14 years, she published two official histories of World War II, The British War Economy (with Sir William Keith Hancock, 1949) and Civil Industry and Trade (with Eric Hargreaves, 1952). After being told that she had no chance of being promoted, she started looking for another job. She was offered the position of official historian and archivist for the the United Kingdom Atomic Energy Authority (UKAEA) in 1959. Among other things, it involved writing the history of the British atomic project from its beginnings. The first book, Britain and Atomic Energy, 1935–1945, was published in 1964. With Lorna Arnold, she then produced a monumental two-volume work, Independence and Deterrence: Britain and Atomic Energy, published in 1974. In 1966, Margaret Gowing became a reader in Contemporary History at the University of Kent, and in 1972, she was appointed to the newly created Chair of the History of Science at Oxford University, a position she held until her retirement in 1986. As co-founder with physicist Nicholas Kurti of the Contemporary Scientific Archives Centre in Oxford, she also helped ensure the preservation of contemporary scientific manuscripts.