Christian Topalov, a sociologist, is a “directeur d’études” at the EHESS and a member of the Centre Maurice Halbwachs (CNRS/EHESS/ENS). His research interests are the comparative study of early 20th c. reform and reformers in Britain, France and the U.S., the history of the social sciences in relation to reform, and the contemporary reform of universities and research organizations in France. Among his personal books : Naissance du chômeur, 1880-1910 (Albin Michel 1994), Histoires d’enquêtes. Londres, Paris, Chicago, 1880-1930 (Classiques Garnier 2015) and La ciudad. Saberes, poderes y lenguaje (Mexico and Buenos Aires 2023). Among his edited books : Laboratoires du nouveau siècle (Editions de l’EHESS 1999), L’Aventure des mots de la ville (Robert Laffont 2010) and Philanthropes en 1900. Londres, New York, Paris, Genève (Créaphis, 2019). He edited the manuscripts and articles the French sociologist Maurice Halbwachs wrote when he visited the University of Chicago in the Fall of 1930 (Ecrits d’Amérique, Editions de l’EHESS 2012). His last book (with Joël Laillier) : Gouverner la science. Anatomie d’une réforme 2004-2020 (Agone, 2023) is a sociological study of the reformers of the French university and research system in the 21st c. He is presently working at a book on bourgeois mobilizations for reform in Paris in 1900.