The monograph examines the legal foundations of the Russian autocracy as a form of the political structure of Russia in the historical concept of P.N. Milyukov. The inconsistency of the sociological method of research is revealed, as well as sociology itself as a science. The author pays the main attention to the results of Milyukov's use of sociological methodology in his analysis of the history of the emergence and development of the political system of Russia.