This is the long-awaited second edition of this widely-referenced work on the substantive law principles of investment treaty arbitration. It forms a detailed critical review of the substantive principles of international law applied by investment arbitration tribunals, and a clear and comprehensive description of the present state of the law. The first edition met with immediate success as a result of the authors' achievement in describing and analyzing the volume of law created, applied and analyzed by tribunals. The second edition is fully updated to take account of the arbitration awards...