Ce volume reunit cinq communications presentees dans le cadre des Conferences d'etudes iraniennes Ehsan et Latifeh Yarshater, organisees en 2010 par l'Unite Mixte de Recherche 7528 Mondes iranien et indien au College de France ... Paris. Il presente de maniere diachronique de nombreuses donnees qui illustrent la confluence de themes mythiques et folkloriques de la culture iranienne, de l'epoque pre-islamique ... nos jours. Cette transversalite de la litterature mythique et populaire, orale et ecrite, trop peu etudiee jusqu'ici, est examinee ... travers cinq themes - Kakil, heros d'une fete hivernale; un charme contre les scorpions; le rossignol et la rose; le songe du roi-sage Xusro Anosirvan; et le saveur eschatologique et son cheval - en prenant en compte des epoques differentes, meme depuis l'Avesta, les sources parthes et sassanides, la poesie des auteurs du Xorasan, le Sahname, le Moyen Age classique jusqu'... l'aube de la revolution islamique. This volume contains the text of the five Ehsan and Latifeh Yarshater Distinguished Lectures on Iranian Studies, organized by the Unite Mixte de Recherche 7528 "Mondes iranien et indien," and delivered in 2010 at the College de France in Paris. The series of lectures brings together numerous data illustrating the confluence of mythological, folkloric and literary themes of Iranian culture, and their continuity from pre-Islamic till present times. This interaction between the classical and popular, oral and written traditions, still little investigated, is being examined on the examples of five motifs: Kakil, the hero of a winter festival; a spell against scorpions; the rose and the nightingale; a symbolical dream of the wise king Xusro Anosirvan; and the eschatological saviour and his horse. The study is conducted in a diachronic perspective, and its sources range from the Avesta and Pahlavi texts through the Sahname and classical Persian literature, up to modern Persian novel and research on popular customs and beliefs.