Langevin grew up in the Montmartre district in the aftermath of the violence of the Paris Commune. His background hardly predestined him for a brilliant career as a physicist, but he benefited from the educational system introduced by the French Third Republic. Langevin graduated top of his year at the École municipale de physique et de chimie industrielles de Paris (EPCI) in 1891. Continuing his education at the prestigious École normale supérieure he was ranked first in the agrégation of physics in 1897, in addition to making many life-long friends. The world of physics was febrile, with X-rays, radioactivity and ether, challenging experimentalists and theoreticians who were conflicted in their approaches. A year’s scholarship with J.J. Thompson in Cambridge, the basis for his PhD in gas ionization in 1904, gave him a springboard for a dazzling career. His 12 publications that year included topics as disparate as gas ionization, the inertia of energy, the ether and kinetic theory, followed the next year by seminal contributions to Brownian motion and magnetism.