James Till

James Edgar Till OC OOnt FRS FRSC (August 25, 1931 – May 18, 2025) was a Canadian biophysicist at the University of Toronto, best known for demonstrating – in a partnership with Ernest McCulloch – the existence of stem cells. Till was born on August 25, 1931, in Lloydminster, which is located on the border between Saskatchewan and Alberta. The family farm was located north of Lloydminster, in Alberta; the eastern margin of the farm was the Alberta–Saskatchewan boundary. He attended the University of Saskatchewan with scholarships awarded by the Standard Oil Company and the National Research Council, graduating with a B.Sc. in 1952 and a M.Sc. in physics in 1954. Some of his early work was conducted with Harold E. Johns, a pioneer in cobalt-60 radiotherapy. Till proceeded to Yale University, where he received a Ph.D. in biophysics in 1957. He then became a post-doctoral fellow at the University of Toronto. Harold E. Johns recruited Till to the Ontario Cancer Institute at Princess Margaret Hospital shortly after he completed his work at Yale. Subsequently, Till chose to work with Ernest McCulloch at the University of Toronto in its Faculty of Medicine. Thus, the older physician's insight was combined with the younger physicist's rigorous and thorough nature.