The work of the Byzantine Emperor Constantine VII Porphyrogenitus “On the Administration of the Empire” is the most important source for the study of Russian history of the 9th–10th centuries. and individual events of previous centuries: it presents a variety of material covering the ethnic, economic, social and political history of the states and peoples that once inhabited our territory, in the context of the general European and Middle Eastern situation of the era. The work is published in its entirety: Greek text, translation, commentary, exhaustive for texts related to our territory, and summary for the rest.