By the mid-twentieth century, French geographers had produced substantial works of research aiming to classify genres de vie. They had broken with the idea that nomadic and sedentary genres de vie were the successive stages of a universal history of human societies, and argued instead that they were the result of human adaptations to speci␣c natural environments. Within this new conceptual framework, nomadism was thus understood as a form of highly evolved genre de vie responding to the particular characteristics of the steppe. But if pastoral nomadism was the best possible adaptation to the dry steppe zone, on what natural basis could the extension of European sedentary agriculture be justi␣ed? Scienti␣c answers to this question were of st...