The book presents the various sociological theories of differentiation in modern societies. It aims to highlight the continuous development of this theoretical perspective from the classical sociologists to the present day and to demonstrate that it contributes essential insights for understanding modern societies. The book received the René König Textbook Award. The justification states that it is written in a clear, understandable language; the reader is guided through the conveyed content in a consistent line of thought; the presented positions and approaches are clearly distinguished according to established comparative criteria; the comparison is made both diachronically and synchronically; the strengths and weaknesses of the shown approaches are clearly highlighted.