For close to 100 years, following the first opium war in 1843, Britain, the US and other treaty powers ran their own legal systems in China under the rule of Extraterritoriality. Similar courts operated in Japan for over 40 years. These courts were essential to maintaining Western presence in China and drove Japan to reform its own legal and political system, making it in turn the most powerful country in Asia. British and Americans were not subject to Chinese and Japanese law and all civil and criminal cases were heard in British and American courts. The cases and the conflicts with locals tell from a unique angle the story of foreign engagement with China and Japan. This book tells the story of Extraterritoriality, the courts and the cases, judges and lawyers, criminals and victims, and offers thoughts on how it changed the history of East Asia.