The immunity or exemption enjoyed by States from legal proceedings before foreign national courts is a crucial area of international law. On the basis of an exhaustive analysis of judicial decisions, international treaties, national legislation, government statements, deliberations in international organisations as well as scholarly opinion, Xiaodong Yang traces the historical development of the relevant doctrine and practice, critically analyses the rationale for restrictive immunity and closely inspects such important exceptions to immunity as commercial transactions, contracts of employment, tortious liability, separate entities, the enforcement of judgments, waiver of immunity and the interplay between State immunity and human rights. The book draws a full picture of the law of State immunity as it currently stands and endeavours to provide useful information and guidance for practitioners, academics and students alike.