The monograph is devoted to the characterization of mass sources on the history of the landowner economy of European Russia in the era of capitalism (materials of patrimonial funds, zemstvo-statistical surveys of private ownership, descriptions of estates mortgaged in land banks, agricultural censuses and other materials), as well as methods of their processing and analysis based on a systematic approach and the use of quantitative methods and computers. The book analyzes the internal structure of the landowner economy of European Russia as a whole and in certain regions on the eve of the Great October Socialist Revolution according to the land agricultural census of 1917.