This book argues that a sustainable and effective legal framework cannot be achieved solely through stronger investor protectionbroader regulatory powers. Rather, it s an appropriate balance between the legitimate expectations of investors and the sovereign authority of States to pursue public policy objectives. Throughout this study, particular attention is given to the interaction between national energy policies, international investment treaties and energy investment contracts, which together form the legal architecture governing international energy investments.

The central premise of this book is that these three components should not operate independently. Instead, they should function as complementary elements of an integrated legal framework, which this book refers to as the "triangular legal framework." This framework is intended to reduce disputes, improve legal certainty and promote sustainable energy investment by strengthening coherence between domestic and international legal instruments while preserving an appropriate balance between public and private interests.

Although this work originated as a doctoral dissertation, it is written with the hope that it will be of practical value not only to scholars and students, but also to arbitrators, practitioners, policymakers and government officials engaged in the development and application of international energy investment law. It is also hoped that the ideas presented herein will contribute, however modest a way, to the continuing discussion on the future evolution of international investment law in the context of by sustainability, energy security and the global energy transition.