FrancisDUCK is a retired medical physicist. During his career developing many aspects of the medical uses of ultrasound, he worked at University College Hospital, London,Memorial University of Newfoundland, the Mayo Clinic, Minnesota, the Institute of Cancer Research UK, and finally in Bath. He has published widely. His 1990 Physical Properties of Tissue remains a key source book. Since retirement he has followed his interest in the history of medical physics. His historical review, Physicists and Physicians, was published in 2013 and his joint biography of the early radiological sisters Edith and Florence Stoney, was published in 2019.The 150^th anniversary of Langevin’s birth in 2022 has brought himback to his roots in ultrasonics.