The book is based on a complete translation into English of the 1987 biography, Langevin 1872-1946 Science et Vigilance by Bernadette Bensaude-Vincent. This new book includes some important revisions to the original text with numerous additional figures. The description of Langevin's work in ultrasonics has been developed and expanded, including much new detail.

French physicist, student of Pierre Curie, close friend of Marie Curie and Albert Einstein, Paul Langevin was one of the handful of influential European physicists who created modern physics at the beginning of the twentieth century. Scientifically, he is remembered particularly for his contributions to the atomic theory of magnetism, for the understanding of relativity and for his work on statistical kinetics. This establishes the context for his role as the 'originator of modern ultrasonics' during the First World War, and his influence on its growth as a scientific speciality during the subsequent two decades. Leading educationalist, he promoted education for women, and science as a core subject. He viewed science as a common good, to be shared for the benefit of all mankind, at a time of growing nationalism. The book focuses also on his political activism as a rationalist and humanist, including his public anti-fascist stand and communist sympathies leading to his house arrest during the Second World War. This portrait of a committed scientist regains a special relevance in the 21st century.

Autorentext

**Bernadette Bensaude-Vincent is a French philosopher, professor emeritus at University of Paris 1 Pantheon-Sorbonne and a member of the French Academy of Technology. Bensaude-Vincent has published more than twenty books and 150 articles and essays. In 1993 she published Histoire de la chimie with Isabelle Stengers, which was translated into English as A History of Chemistry in 1997. The authors received the Prix Jean-Rostand for this work. In the early 1990s, Bensaude-Vincent directed a research program on science and the public. In 1997, she was appointed professor of History and Philosophy of Science at Université Paris-X Nanterre. Laterly she has called for a new alliance between science and ethics, co-directing a joint ANR/DFG project which sought to distinguish between science and technoscience. Between 2010 to 2015, she was a professor at the University of Paris 1 Pantheon-Sorbonne and the director of The Center for Study of Technology, Knowledge & Practice (Centre d'étude des techniques, des connaissances et des pratiques, CETCOPRA). In addition she has been a visiting professor at various universities around the world, a visiting scholar at Max Planck Institute for the History of Science in Berlin (2001) and Doctor Honoris Causa of Lisbon University in 2017. In November 2021 she received the George Sarton Medal, the highest distinction of the History of Science Society, the Franklin-Lavoisier medal in 2024, and an award from the Society of Technology and Philosophy in 2025.

**Francis Duck is a retired medical physicist and, until 2018, visiting professor at the University of Bath UK. He has degrees from the Universities of Nottingham (BSc in Physics) and London (PhD, DSc). He spent time in research in medical ultrasound in the UK, Canada and the USA, and then made his career as a medical physicist in the UK National Health Service. He is author or co-author of 92 peer-reviewed papers and four books, including Edith and Florence Stoney, sisters in radiology, co-authored with Adrian Thomas and published in 2019 as a Springer Biography, which gained a 3-star Doody rating. He helped to define safety boundaries for the diagnostic use of ultrasound, and serving on committees with the IEC, the World Federation for Ultrasound in Medicine and Biology, the American Institute for Ultrasound in Medicine, the European Federation of Societies for Ultrasound in Medicine and Biology, and the UK Health Protection Agency. Since retirement, he has published widely on the history of physics applied to medicine, and most recently has edited and contributed to a history of medical ultrasound with the International Organisation for Medical Physics. In 2007 he was awarded the MBE for services to health care.