Augustin Cournot : modelling economics 1. Cournot as economist : 200 years of relevance Jean Magnan de Bornier 2. Cournots probabilistic epistemology Thierry Martin 3. The functions of economic models Bernard Walliser 4. From Cournots principle to market efficiency Glenn Shafer 5. War and peace Robert J. Aumann 6. Cournot and the social income Robert M. Solow 7. Comparing the incomparable : the sociology of statistics Alain Desrosières. From his earliest publications Cournot broke from tradition with his predecessors in applying mathematical modelling to the social sphere. Consequently he was the first to affirm the mathematization of social phenomena as an essential principle. The fecundity of Cournots works stems not only from this departure but also from a richness that irrigated the social sciences of the twentieth century. In this collection the contributors including two Nobel laureates in economics highlight Cournots profound innovativeness and continued relevance in the areas of industrial economics mathematical economics market competition game theory and epistemology of probability and statistics. Each of the seven authors reminds us of the force and modernity of Cournots thought as a mathematician historian of the sciences philosopher and not least as an economist