The fifth edition of this book that appeared in 2003 has been extensively revised. To mark the growing importance of the international prosecution of alleged war criminals and others accused of egregious crimes, a new chapter on Individual Criminal Responsibility in International Law has been introduced. The chapter on Air and Space Law has had to be removed, with the section on Outer Space being moved to the chapter on Territory. The increasing significance of the International Court of Justice is recognised by devoting a separate chapter to it. The section on the International Tribunal for the Law of the Sea has been moved to the chapter on the Law of the Sea. The other chapters in the book have been re-examined, updated and, where necessary, rewritten.