The question of the true historical roots of modern Ukrainians and Russians is the subject of a thorough study of S. Plohiy in the book "The Origin of Slavic Nations. Pre-modern identities in Ukraine and Russia. " Based on reliable sources, the author studies the conflicts of the struggle for the heritage of Kievan Rus based on the analysis of pre-modern group identities of Eastern Slavs, common and different in their cultures, historical myths, ideologies, self-esteem and others, etc. This version of the publication consists of three essays ("Was there a" reunification "?", "Birth of Russia" and "Russia, Little Russia, Ukraine") covers the period of formation and awareness of Ukrainian statehood - from the mid-seventeenth to mid-eighteenth century - and aims to shake the established tradition of treating East Slavic peoples pre-designated ancestral formations transferred to ancient ethno-centric nations. Identity is the core of a nation's identity and is always on the move, depending on the age and circumstances of the "program," says this groundbreaking compelling study recommended by Western and Russian reviewers as a must-read for anyone studying Slavic history and Eastern European history.