It was said a few years ago that if the human race is wiped out in the next 50 years it will not be because of disease or an asteroid hitting the earth, but because of foreign policy and international relations. In a world where thousands of nuclear weapons exist and more countries are trying to acquire them, where suicide terrorist strikes come without warning and thousands die each day from poverty caused by the way the international system operates, we need to know about and understand international relations. This book is an endeavour about all those aspects which plays one and another role in influencing international relations like approaches and ideology of different states, nation- state system , national interest, national power, balance of power , collective security, non- alignment and international law. As far as from historical perspective, this book coves the historical factors which are responsible for developing international relations, like Impact of cold war, emergence of two blocs, disintegeration of soviet union and establishment US hegemony in the international politics.