Born in London, England, Leonard Charles Marsh (1906–1982) was a highly influential social scientist and professor. He studied at the London School of Economics and Political Science, where he worked with William Beveridge, author of the Beveridge Report, as a graduate student. In 1930, Marsh immigrated to Canada to direct an interdisciplinary social science research program at McGill University, where he was also active in promoting the study of social questions and was a founding member of what became the League for Social Reconstruction. Marsh’s expertise won recognition, and Dr. F. Cyril James, Principal of McGill and Chair of the Advisory Committee on Post-War Reconstruction, commissioned him to study Canada’s social programs and write a report. Marsh’s Report on Social Security for Canada was comprehensive, detailing the universality of the risks of illness and disability for all Canadians, as well as the means of establishing and funding a social security system for Canada. Many of the recommendations in the report had become law by the early 1970s, making Marsh an architect of Canada’s social security system.