The doctrine of State immunity bars a national court from adjudicating or enforcing claims against foreign states. This doctrine, the foundation for high-profile national and international decisions such as those in the Pinochet case and the Arrest Warrant cases, has always been controversial. The reasons for the controversy are many and varied. Some argue that state immunity paves the way for State violations of human rights. Others argue that the customary basis for the doctrine is not a sufficient basis for regulation and that codification is the way forward. Still others argue that even when judgements are made in national courts against other states, the doctrine makes enforcement of these decisions impossible. This fully restructured new edition addresses all of these issues by reference to the United Nations Convention on Jurisdictional Immunities of States and their Property. Through a detailed examination of the sources of law and of English and US case law, and a comparative analysis of other types of immunity, Hazel Fox explores both the law as it stands, and what it could and should be in years to come.