Nikolai Ivanovich Kareev (1850–1931) — prominent sociologist and historian, one of the originators of Russian sociology, represents its psychological field. The major problematic domains of the research are the method of social cognition; collective psychology as the basis of the society; the historical process. Kareev’s review is dedicated to the work of Pitirim Aleksandrovich Sorokin “The system of sociology”. It was written in the autumn of 1920 and delivered as a lecture at the Russian sociological society M.M. Kovalevsky session.The review covering P.A. Sorokin’s ideas consists of 6 parts. In the first part of the review the author states that there are many trends in Russian sociology such as organicistic, evolutional, psychological and economic. In the second part he briefly reviews P.A. Sorokin’s concept and notices its mechanicalness. The third and the fourth part are dedicated to the analysis of the concept of individual interaction. In the fifth part he investigates the principles of collective (elementary and cumulative) unities based on the individual interaction. In the sixth part he writes about the position of the individuality in the social coordinative system. The review is the most detailed (or comprehensive) overview of the young sociologist’s work. The main objects of the Kareev’s criticism are the method of reflexology that was developed and supported by Sorokin at that time, also his mechanistic representation of a personality in the social frame of axis. Despite the seeming criticism the article is benevolent: in 1922 Kareev was opponent on the public dispute of P.A. Sorokin. The document was discovered in the N.I. Karrev’s private fund in the Scientific-research department of manuscripts of the Russian State Library and is published for the first time.