PAUL LANGEVIN (1872-1946) was a renowned French physicist, humanist, and educationalist. This biography by his son André, originally published in French in 1972 and here translated into English for the first time, is enhanced by numerous quotations from his friends, scientific and political colleagues, family and by Paul Langevin himself. Close to the Curies, Einstein, and Rutherford, this is a vivid account of a life lived at the core of physics turned upside down by the discovery of radioactivity and X-rays, by the theory of quanta, by relativity and by wave mechanics. Langevin himself was the originator of ultrasonics, a p ...