In recent years, there has been a marked increase in the number of investors seeking compensation from states perceived to have expropriated their projects. Part of the Oxford International Arbitration Series, this work provides a comprehensive guide to expropriation and how it is applied in practice. The author offers a detailed examination of existing case law, from which common substantive principles of the international law on expropriation are drawn out. Relevant international cases from the ICJ, ECHR, and Iran-US Tribunal are considered to complement the focus on investment treaty arbitration and ICSID, UNCITRAL, NAFTA and ECT cases. The book examines the interplay between expropriation and other standards of treaty protection, such as fair and equitable treatment, as well as remedies for expropriation. The reader embarks on a thorough examination of expropriation in investment treaty arbitration, from its evolution into an accepted principle in international law today, through to current trends and a critical assessment of the relevance of expropriation in the present day. Expropriation in Investment Treaty Arbitration is a useful, systematic analysis of a topic that is of vital importance in arbitration practice, a key resource for all practitioners in this field.