The paper examines Gusti’s thesis on sociology, nation, nation’s science and the significance of sociological monograph in support of the nation’s science. I am trying to argue with the idea of interpenetration between sociology, science of social reality, and the science of the nation. In my opinion, in Gusti’s doctrine, the approach to the relationship between sociology and the science of the nation remains fundamental.I propose the analysis of this theme in the study of its evolution in the Gustian doctrine outlined in the works: Introduction to the Course of the History of Greek Philosophy, Ethics and Sociology, 1910; The Problem of the Nation, 1919; The Science of the Nation, 1937; Considerations on a System of Sociology, Ethics and Politics, 1940; Science and Pedagogy of the Nation, 1941. At the same time, I argue about the configuration of his sociological, ethical and political system in the inaugural lecture of 1910, inadequately studied by the Gustian exegesis.The paper has three parts. In the first part, Dimitrie Gusti’s sociological system, I discuss sociology as a science of social reality, social will, social units and society. In the second part,  The nation’s science and the sociology of nation, I present the concept of nation, state and nation, the science of the nation, the federation of European states, the exegesis of Gusti’s ideas on the science of the nation. The third part, The Sociological Monograph, describes Gusti’s conception of empirical research.

Keywords: science of social reality, science of nation, sociology of nation, social units, monography.

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