Lucy Joan Slater was born in Parkstone, Dorset, on 5 January 1922, the only child of John Wardle Slater, chemist, and Lucy Dalton, Classics scholar. She and her parents moved to Portsmouth in 1928. She was partly self-educated and partly taught by her mother until 1938. She then attended Portsmouth Technical College from 1938 to 1942, followed by University College, Southampton from 1942 to 1944, achieving a London University external general BA degree in mathematics and music in 1944. She taught mathematics at Winchester County High School for Girls from 1944 to 1945 and gained a teaching diploma in 1945. In 1945 she returned to University College, Southampton to study for an honours degree, achieving the London external honours BA in 1947. She was a postgraduate student at Bedford College, London, from 1947-49, and later a Research Fellow there, achieving her London MA by thesis in 1949 and a London PhD in 1951. From 1951-53 she was a research student at Girton College, achieving a Cambridge PhD in 1953. She then became Bateson Research Fellow at Newnham College from 1953-56. From 1951 to 1956 she undertook research in the Cambridge Mathematical Laboratory on hypergeometric functions and computers, playing a substantial role in devising a precursor of modern computer operating systems. She then held a number of posts in the Department of Applied Economics, with particular emphasis on the use of computers, including early computerisation work for the London Stock Exchange. She advised on the setting up of a Computing Laboratory at the University of Essex in the mid-1960s. She was awarded a London D.Litt in 1956 and a Cambridge Sc.D in 1968. She was appointed a Governor of Bedford College, London, in 1956. In retirement, she was active in family history and genealogy. She became an Honorary Member of Lucy Cavendish College, Cambridge, in 1982. Lucy Slater died on 4 June 2008 in Cambridge.