The increase in the number and complexity of investor-State treaty arbitrations in the last decade has attracted considerable attention from practitioners and academics of international investment protection law. Rules aimed at regulating the protection of foreign investment have been expressed in a decentralised manner, making a clear and comprehensive overview of the topic important. This volume focuses on the relevant documents and aims to provide an exhaustive treatment of relevant procedural and substantive issues. It includes documents explaining the historical development of investment law, substantive investment rules (multilateral and bilateral treaties and model documents, and general rules on the law of treaties and responsibility) and procedural investment rules (relating to the arbitral process in different fora, immunity, recognition and enforcement). The book is aimed at teachers, students and practitioners in the area. It can be used both as a practitioners' handbook and as a classroom companion for courses on international dispute settlement and investment protection law.