Is a professor of the history of medicine and pharmacy at the University of Bern. He was the president of the International Society for the History of Pharmacy for many years. He is a corresponding or honorary member of numerous pharmaceutical history societies in France, Spain, Italy, Benelux, Romania, and the German Society for the History of Pharmacy. Ledermann has published extensively on the development of pharmacy in Switzerland and on the history of pharmaceutical culture. Currently, he works at the Institute of the History of Medicine of the University of Berne where he leads the Historical Library of Swiss Pharmacy.