This book deals with the so-called absolute standards of investment protection in international investment law: the fair and equitable treatment (FET) and full protection and security (FPS) standard. It tries to answer the question whether extraordinary circumstances prevailing in host States have an influence on the interpretation of these standards. To this end, the author investigates the normative foundations of both standards, including their ordinary meaning, context, and purpose, before analysing the existing arbitral tribunals interpretations.