The publication of this volume has been a collaborative effort made possible as a result of various types of support and financial assistance that we have received from a number of sources, and we are pleased to record, in this formal way, our thanks to those people and institutions.

Many of the chapters in this volume were first presented at a conference, entitled ‘Investment Treaty Law and Arbitration: Evolution and Revolution in Substance and Procedure’, which was hosted by Sydney Law School, the University of Sydney, Australia, on 19–20 February 2010. That conference was made possible by a Research Development Grant under the New Capacity Programme from the Institute of Social Sciences at the University of Sydney, a Conference Seeding Grant from Sydney Law School and further financial assistance from the Sydney Centre for International Law; the Centre for Asian and Pacific Law at the University of Sydney; and the Parsons Centre of Commercial, Corporate and Taxation Law, each of which are housed within Sydney Law School. Additional sponsorship for the conference was generously provided by Allens Arthur Robinson, Blake Dawson, Clayton Utz and Mallesons Stephen Jaques.

International investment law is a well-established discipline grounded in principles of customary international law that stretch back into the nineteenth century. In recent times, however, it has become quite evident that the law is in a state of flux. In particular, with the advent of investor–State arbitration in the latter part of the twentieth century, new levels of complexity, uncertainty and substantive expansion have been emerging. Indeed, in many ways, a discrete field of investment treaty law has developed, largely driven by the exponential growth in investment treaty arbitration over the last decade. Together with the continued proliferation of bilateral investment treaties (BITs) as well as the more recent trend of States concluding free trade agreements (FTAs) containing investment chapters, the now often very detailed reasoning set out in an increasingly large number of arbitral awards has contributed to rapid developments in the field. Such change has reached into almost all areas of investment treaty law and practice, encompassing the interpretation of substantive obligations, an intensified focus on procedural matters, the participation of new actors and the more nuanced content of recent BITs. In many investment treaty awards, the tribunals undertake a close examination of previous investment treaty decisions, leading to the creation of what is now being regularly described as an investment treaty jurisprudence.

This acceleration of activity does not, however, indicate consensus. On the contrary, investment treaty law and arbitration has very much become a high-profile area of contestation. In this regard, the controversy is not only reflected in the continuing debates on the implications of substantive rules, but there has also been a discernible shift towards the consideration of systemic issues, such as the ‘legitimacy’ of the investment treaty system, its interaction with other areas of international law, the role of economic development in the regime, the problem of inconsistencies in awards and related procedural issues such as challenges to arbitrators and the need for greater transparency. It is, therefore, an opportune moment to take stock of the point at which investment treaty law and arbitration has arrived and to reflect on the processes currently unfolding within the field.