In this issue, we try to provide some thoughts on the use of experts in arbitration and litigation. While the stated focus in on the energy sector, some of the authors have written for a more general audience. Some articles are written by the experts; others about them. The authors and I hope that the reader will find some matters of interest, perhaps even something new or controversial. With a little luck, our straying a bit off course from time to time will not be without good purpose.

Trying to organize a diverse set of articles into some (hopefully) meaningful categories to assist the reader in navigating the issue is a bit of a challenge - some articles simply don't fit well into a particular pigeon hole. But given sufficient brute force, I will try to force the round peg into the square hole, with the following general categories of papers:

• General Witness Articles: We start the issue with an introductory article by Baiju Vasani providing some basic guidance for the expert who is new to international arbitration. Rachael Kent follows up with some distinctions between expert witness practice in litigation and in international arbitration. Having experience with both, I have taken editorial license to pen a comment to Rachael's fine article. We follow that with Ahmed El-Kosheri's thoughts on the different types of experts. Richard Kreindler addresses the task of benefiting from oral testimony of experts. Claus von Wobeser focuses our attention on the use of tribunal-appointed experts, and Martin Hunter rounds out this section with a discussion of expert conferencing and other methods of obtaining the information the tribunal needs to decide the case.

• Finance and Damages Theory: Our next section launches the reader into the world of finance and quantum issues. Manuel Abdala and Pablo Spiller set forth their thoughts on damage valuation in indirect expropriation cases, and follow that up with a paper authored with their colleague Sebastián Zuccon on their experience in the recent arbitration between ADC et al and Hungary, a case also discussed by Richard Deutsch, who takes a closer look at the impact of this case on upcoming expropriation claims. Mark Kantor introduces the topic of adjusted book value as a method of valuation, while Thierry Senechal follows up with a paper contrasting the adjusted present value method with the discounted cash flow method.

• Legal Perspectives: We take a brief interlude and shift from the expert side of the table to the lawyers, which will be a relief to those counsel who simply abhor numbers. Guillaume Lemenez de Kerdelleau offers an analysis of whether Article 22 of the Venezuelan Investment Law serves as consent to ICSID arbitration, a topic that has been discussed with some recent frequency in the OGEMID discussion forum.

• Market and Commercial Issues: Next we present a series of articles from experts in market and commercial issues affecting the energy investor. Denis King and Arif Aliset forth some thoughts on technical matters and contract milestones in the construction of power generation facilities. Next, Nels Pearsall, discusses how The United States Patent and Trademark Office ("USPTO") patent data might be used to identify and understand relevant trends occurring within patent classes relevant to participants in energy related industries. Wayne Wilson, Aaron Stai, Jason Cain, Jason Scholler and Sandra Weisbrod address nationalization and other issues faced by multinational oil companies.

• Climate Change Issues: No special on energy issues would be complete without at least a brief mention of climate change, and this publication is no exception. Adaeze Nwakoby looks at the effect of emissions trading on market actions, a bit of a primer for those not intimately familiar with emissions trading schemes. Liz Bossley follows up with an article on the Kyoto Clean Development Mechanism. We close our issue with C. Baird Brown, David Mandelbaum, Robert McKinstry, Jr. and Glenn Unterberger writing about the state climate change policy initiatives in the United States.

I wish to thank, first of all, Thomas Wälde and the OGEL/TDM publishers for the opportunity to prepare this special issue, and especially all of the authors for their hard work in preparing the papers in this issue. I would also call the reader's attention to the anticipated autumn 2007 publication of a special issue on compensation, being edited by Dr. Irmgard Marboe at the University of Vienna. Perhaps this issue can provoke some responsive comments in OGEL and TDM that might be included in Dr. Marboe's publication or elsewhere in the OGEL and TDM sphere. If we can spur some discourse, or maybe even outright argument, tant mieux!

Fairfax, Virginia
June, 2007

Richard E. ("Rory") Walck is the founder and President of Global Financial Analytics LLC, a consultancy providing financial analysis and expert witness services in investment treaty and commercial arbitration and litigation. He has more than thirty years of experience consulting and testifying on a variety of matters in State and Federal courts, as well as in ICC, ICDR, UNCITRAL, ICSID, AAA and ad hoc proceedings.