The book consists of three chapters, written by different writers, analyzing the main findings of the research undertaken by the Institute for Sociological Research (“Demographic and Social Development of Municipal Local Communities in the Socialist Republic of Serbia 1961–1971″ and “Sociological Dimensions of Underdeveloped Regions in SR Serbia”). The book addresses topics such as population growth and reproduction in Serbian municipalities, urbanization and deagrarization, types of fertility and reproductive behavior, social, economic and demographic differences between local communities, as well as the sociological dimensions of the underdeveloped regions. The main significance of the book lies in its rich empirical evidence that illustrates changing properties of the population caused by the intense social and territorial mobility and social differences between municipalities in the period 1961–1971.