This chapter reviews the relative success of the United Nations Convention on Contracts for the International Sale of Goods (CISG) in harmonizing international sales law. It questions the worth of the CISG when private parties often opt out of its coverage. It begins first at the grass roots of law application and asks – Have the CISG text and principles, and their application, set the foundation for a relative uniformity of application? Has there been a convergence in CISG jurisprudence towards more uniform interpretations? What remain as the key issues in dispute? What are the current trends in CISG jurisprudence? Can we speak of majority and minority views? Rule and principle applications often generate a list of factors that the courts look to in their application. What factors analyses have been developed to guide the courts and arbitral tribunals in applying CISG Articles to different real world contexts? Have implied principles and implied default rules been developed to fill in the gaps in the CISG text?

The chapter asks what are the possible “future” roles of the CISG in harmonizing international sales law. The areas to be analyzed include whether there will be a (1) continuance of current trends towards substantive convergence, (2) further increase in operational usefulness, (3) increased use as customary international law? (4) continued use of it as a model for modernization of domestic sales and contract law. Question (1) builds on the first part of the chapter, that shows a substantive convergence of divergent, autonomous interpretations of CISG articles. Question (2) deals with the problem of private ignorance and avoidance of the CISG through the exercise of the right to opt out. The obvious solution to this problem will be explored: the education of the legal and business communities on the benefits of using the CISG as choice of law (opting in) and how it can be used strategically on behalf of buyers and sellers. Question (3) deals with the lackluster use of the CISG as evidence of international customary law, with a focus on its use as such by arbitral tribunals. Question (4) may in the end be the most important – the impact of the CISG as a model for the modernization of domestic contract law.