This book reviews and examines the relevant portions of all international treaties, cases and the national law and practice of states, in relation to international aspects of offshore oil rigs. By doing so, it offers an understanding of the legal regime surrounding oil rigs and formulates an international law framework. It investigates the issues under consideration by analyzing provisions of international law pertaining to all aspects of oil rigs, as well as international treaties and their travaux preparatoires. It also examines the national legislation of major offshore oil and gas producers and defines a framework of customary international entities such as the OSPAR and the petroleum industries of certain major offshore oil producers. Based upon the book's findings, it is clear that in spite of their increasing importance, offshore oil installations are subject to fragmentary and vague legal rules under international law.