States' efforts to reform the international investment regime have triggered an arbitral backlash. In response to shortcomings of earlier investment agreements, states concluded a new generation of investment treaties that actively balances investment protection obligations with host country policy space. These new-generation agreements are more comprehensive, more precise, and include novel features such as general public policy exceptions. This book reviews the first set of awards rendered under those agreements and finds that new treaties have produced old interpretive outcomes in investment arbitration, and undermine state-driven investment reforms. Adopting a systemic, evidence-based, and interdisciplinary perspective, the book leverages new data that comprehensively reflects regime dynamics, employs state-of-the-art technology including legal data science to treat the text of more than 3000 investment agreements as data, and draws from a range of theoretical frameworks spanning from law and economics to complexity science. The result is a new and authoritative empirical account of the evolution and current state of the international investment regime.