Political theory is more concerned with contributions of various classical thinkers such as Chanakya, Aristotle, Machiavelli, Cicero, Plato and many others. Comparative politics is the science of comparison and teaching of different types of constitutions, political actors, legislature and associated fields, all of them from an intrastate perspective. International relations deals with the interaction between nation-states as well as intergovernmental and transnational organizations.