This book provides an in-depth analysis of "Mega-Regionals", the new generation of trans-regional free-trade agreements (FTAs) currently under negotiation, and their effect on the future of international economic law. The main focus centres on the EU-US Transatlantic Trade and Investment Partnership (TTIP), the Trans-Pacific Partnership (TPP) and the EU-Canada Comprehensive Economic and Trade Agreement (CETA), but the findings are also applicable to similar agreements under negotiation, such as the Regional Comprehensive Economic Partnership (RCEP). The specific features of Mega-Regional Trade Agreements raise a number of issues with respect to their potential effect on the current system of international trade and investment law. These include the consequences of Mega-Regionals for the most-favoured-nation (MFN) principle, their relation to the multilateral system of the World Trade Organization (WTO), their democratic legitimacy and their interaction with existing bilateral investment treaties (BITs). The book is intended for academics and practitioners working in the field of international economic law.