Public International law governs the relations between sovereign states and between international organisations and sovereign states. It is increasingly having an impact directly as well of individuals through the growth in human rights law . States form the basis of the world's political organisation but they are not free to act with impunity. They are creatures of the law, just as individuals and companies are creatures of law.
Public International law is the law that regulates the activities of states, that prohibits the use of force except in self defence and which has given us the United Nations. Public International Law is not always obeyed and the enforceability of international law is one of the big issues.
Important topics also include a discussion of which entities are the subject of international law, what the rules on state immunity provide and what law governs the deep sea bed! Every time you post a letter overseas you are benefitting from international law- the rules on international postage go back centuries! Public international law is important for world peace and with globalisation its place is increasing in importance.