and celebrated interpreter of Leibniz. Couturat’s doctoral thesis was a defence of completed infinite collections. This work led to an interest in Leibniz, and Couturat’s La Logique de Leibniz (1901) placed Leibniz’s logical work at the heart of his metaphysical system. Couturat’s rationalism and admiration for Leibniz’s ideal of a characteristica universalis resulted in his spending his later years prosecuting the goal of an international language.