The study of social structure, social stratification of society is the main topic of sociology. Knowledge of the social structure helps sociologists to perform a creative function to transform society. In the textbook I. I. Podoinitsyna examines the evolution of the views of foreign and domestic scientists on the processes of class formation and stratogenesis, comprehensively discusses the theoretical and methodological approaches to differentiation and analysis of class groups and factors of class formation. The textbook analyzes in detail the post-perestroika socio-structural processes in the Russian Federation, new approaches to the study of social differentiation of society, which began to develop in Russia due to transparency, restructuring, openness to ideological teachings penetrating from Abroad. The profile of social stratification of modern Russia appears to us in a new perspective, as if "bifurcated": we see Russia marginalized and Russia entrepreneurs, Russia, immersed in even greater poverty than we have seen in Soviet times, and Russia new managers, rich people, entrepreneurs and innovators. Exclusive are the chapters of the textbook devoted to the analysis of the regional social structure — in this case, the Yakut society, or the society of the Republic of Sakha (Yakutia). The transformation of the social structure of Yakutia is considered in retrospect, since the XVIII century. The author analyzes the socio-professional, socio-cultural "lattice" of the social structure of the Republic, the ways and lifestyles of the population, the "breakthrough" of the Republic of Sakha (Yakutia) in the information society. The author of the textbook focuses on the methods by which you can study the social structure of society, including the technology of mathematical and statistical analysis. The Republic of Sakha (Yakutia) acts in this textbook as a kind of model of local, regional society, which should be studied by special methods. The tutorial has tests, control questions for each Chapter. Each Chapter is also provided with a detailed summary of the findings of the material presented. The scientific book discusses the prospects for the development of sociology of social structures in postmodern conditions, the emergence of a new approach to scientific truth. A large number of empirical, factual material — the results of studies in Russia and the Republic of Sakha (Yakutia) - is not just illustrative material that enriches the text of the textbook, but also helps to establish a bridge between theoretical and applied methods of analysis, on the example of these studies, the author demonstrates how to interpret the primary sociological data.