International investment law is one of the fastest-growing and most vibrant fields of international law and dispute settlement today. It is both shaped by, and is shaping, the economic and social processes associated with globalization. In fact, it grows at a rate that makes authoring and publishing a book on international investment law an endeavor that evokes Achilles' footrace against the tortoise: an infinite struggle of catching up to a place and point in time that will be past present. Since the initial manuscript of this book was finalized in August 2008 the developments in arbitral jurisprudence, investment treaty making and scholarship have not paused. Instead, they have continued their exponential growth to now over 2,600 bilateral, regional and sectoral investment treaties and over 300 known investment treaty arbitrations that cover increasingly complex procedural and substantive issues and are accompanied by proliferating scholarship on various facets of international investment law. Although the most relevant subsequent developments in arbitral jurisprudence up to March 2009 have been worked into the book, in particular developments concerning the interpretation of most-favored-nation clauses, it can offer no more than a snapshot of where arbitral jurisprudence, investment treaty making and scholarship on international investment law currently stand, or will stand once this book courts for the attention of counsels and arbitrators in investment treaty disputes, scholars and students of international law and international relations, as well as officials in international organizations, domestic governments and non-governmental organizations active in the field.