Talcott Parsons is one of the largest and most interesting theoretical sociologists of the 20th century. The book is devoted to the theoretical development of key concepts for the American sociologist. This is primarily about the concept of "social action," as an ontological unit and a core concept for all social sciences. In this context, the original concept of sociology as a science is built, which includes the general theory of the social system and the theory of social stratification.