Christian Bracco is Associate Professor at the Université Côte d’Azur and a research scientist in th eAstronomical sciences team at the Paris Observatory.Trained as a physicist, he is a recognised specialist in the history of physics of the nineteen and early twentieth centuries in optics, electromagnetism and relativity. He lectures on the history of physics to undergraduate and graduate students in philosophy, to future physics teachers and in physics-intensive doctoral schools.