Based on the analysis of the religious texts of the Rigveda, Atharvaveda, Shatapatha-Brahmana of the Indo-Aryans and Avesta of the Iranians, as well as linguistic data, the book provides a reconstruction of the ancient culture of the Indo-Iranians. Its comparison with specific archaeological cultures of the Old World II millennium BC allows us to consider the Eurasian steppe, primarily Andronovo, tribes that settled from the Urals to southern Siberia, the most likely ancestors of the Indo-Iranians who migrated to Iran and Hindustan through Central Asia.