The Commentary on the UNIDROIT Principles of International Commercial Contracts is written by an international team of distinguished practitioners and academics. They offer an article by article commentary on the principles to provide an accessible guide to the existing case law and legal literature, as well as a comparison with national and international legislation. The UNIDROIT Principles of International Commercial Contracts are the result of the ambitious quest to codify the lex mercatoria; those unwritten rules of the game by which merchants have always understood to do international business. Since the publication of their first version in 1994, the UNIDROIT Principles have been impressively successful. They have become a serious alternative to national contract laws in international disputes decided by arbitral tribunals, such as those administered by the International Chamber of Commerce (ICC). At the same time, they have been accepted as a model for reforming the laws on international contract, by countries such as Russia, Lithuania, and China. With the publication of a new version of the Principles in 2004, this first phase of codifying international contract law is now considered to be finished. This book provides commentary on the substantive rules on contracts with a comprehensive analysis of each provision. As a result, this book aims to increase understanding of the rules governing international contracts and aid the practical application of the Principles.