The book is devoted to the study of the initial stage of development of inter-princely relations in Rus' in the last quarter of the 10th - first quarter of the 12th centuries. (from the death of Svyatoslav Igorevich to the death of Vladimir Monomakh). The work shows the features of “collective co-ownership” in Rus', established at the end of the 10th century, and examines the problem of establishing the priority of “eldership” in the Rurik family, which took shape at the turn of the 11th-12th centuries. The publishing layout of the book is saved in PDF A4 format.