This book explores the interest of one inroad which does not belong to any one individual, organized school or academic group operating today. At its root lies an attempt to bridge a gap using proposals that were common tender in the 1930s and 40s, when a series of scholars from different countries and scientific backgrounds had no qualms about turning to sociology or anthropology, or even psychoanalysis, in order to interpret the physical and material cultural features, as well as religious, mythical and ritual features of the different peoples who were the historical successors of the Indo-Europeans. 18 papers in English and French.