Reaching past the secrecy so often met in arbitration, the second edition of this commentary explains clearly and fully the workings of the UNCITRAL Rules of Arbitral Procedure recommended for use in 1976 by the United Nations. This new edition fully takes account of the revised Rules adopted in 2010 while maintaining coverage of the original Rules where these remain relevant. The differences between the old and the new Rules are clearly indicated and explained. Pulling together difficult to obtain sources from the Iran-United States Claims Tribunal, arbitrations under Chapter 11 of the North American Free Trade Agreement, and ad hoc arbitrations, it illuminates the shape the UNCITRAL Rules take in practice. The authors cogently critique that practice in the light of the negotiating history of the rules and solutions adopted by the other major private rules of arbitral procedure. To aid the specialist in the field, the practice of these various tribunals is extensively extracted and reproduced. Rich both in its analysis and sources, this text is indispensable for those working in or studying international arbitration.