This research paper provides a comprehensive overview of one the key themes of Spinoza’s Philosophy, Emotions and Reason, i.e. man’s rational nature. For a complete insight into Spinoza’s multidisciplinary approach to the aforementioned topic, his most significant works were considered, as well as the additional literature by various domestic and foreign authors. The initial chapter focuses on the introduction of key terminology, on the concepts and definitions of Spinoza’s philosophical vocabulary, as an indispensable tool for grasping his philosophy. This paper further deals with a detailed analysis of emotions, reason and the state, as interconnected concepts, whose understanding Spinoza recognizes as a necessary condition for achieving both individual and collective happiness. According to Spinoza, our God-given nature can be realized exclusively through the primacy of reason. The synthesis of Spinoza’s views on this topic portrays, on the one hand, a picture of his time, and on the other, the ideal to which he personally aspired. His reflections on political reality of the century in which he lived and created are equally relevant today. We have not overcome Spinoza, we did not even come to fully understand him. He thus remains a lasting reminder of human potential and all that we, as individuals and as society, could have accomplished.