Document from the year 2016 in the subject Sociology - Social System, Social Structure, Class, Social Stratification, University of Poznan (Institute of Sociology), language: English, abstract: The book tests the double hypothesis of the death of the middle class. Using U.S. and other developed and developing countries' materials, it seeks to answer whether the popular thesis on its demise is true, and second, it shows it is true in a conceptual sense, viz. , the term in question is a misnomer, referring to a stratum rather than a class. In the course of those investigations other key questions are examined, such as an all-important issue of socio-economic inequality: both in national and world context. The study is underpinned by an original conceptual framework encompassing social class and estate theories and ownership theory. This makes it possible to criticise many other approaches to the problems analysed. For instance, a critique of a well-known book by the French economist Th. Picketty has been undertaken, showing its numerous flaws. In addition, the analysis of the middle class concept demonstrates its defects manifest in its various definitions and usages.