In This Paper We Present About Kautilya's Arthasastra. Itdescribes Not Only the Internal Administration But the External Behavior of Thestate. All the Basic Principles of Inter - State Relations Are Given Inarthasastra. He Agrees With Imperialism and Describes the Way to Win a State.Kautilya Deals With Foreign Policy, So He Is Popularly Known As the Greattheorist of InterState Relations Because of His Unique and Unprecedentedcontribution.