The debate over regionalism and the multilateral trading system intensifies in the WTO as dozens of regional trade agreements are declared to be exceptions to GATT's most-favoured nation obligation. Commentators debate whether such agreements are 'stepping stones' to freer world trade, and WTO Members remain unsettled on criteria to determine the compatibility of agreements with the multilateral trading system. This book addresses legal aspects of GATT Article XXIV and its 'internal' trade requirements as they define the WTO gateway for regional trade agreements.