Professor Léon Sanche obtained a Ph.D. degree from Yale in Engineering and Applied Sciences in 1971. Afterwards, he became an associate professor at the University of Sherbrooke in Canada, where he held a senior Canadian Research Chair in the Radiation Sciences. His general career goal has been and still is to achieve a global comprehension of the mechanisms of radiation in biological systems and to apply this knowledge to enhance the therapeutic and diagnostic efficiency of radiation. To work efficiently toward this goal, he formed a group of the Medical Research Council of Canada in 1982. His research has been essentially focused on the action of secondary electrons generated by ionizing radiation in condensed matter, particularly in biological tissue. Dr. Sanche has published close to 500 refereed papers, including book chapters, and more than 700 abstracts of presentations at national and international meetings. Among these latter, 150 were invited lectures. He trained about 50 students and postdoctoral fellows. He obtained the Distinguished Scientist Award from the Medical Research Council of Canada and more recently the Marie Curie Fellowship for incoming senior scientists from the European Commission. In 2008, he was elected member of the Academy of Sciences of the Royal Society of Canada. Recently, he received the Failla Award from the Radiation Research Society for his achievements in understanding the role of low-energy electrons in radiation sciences.