One of the most important treaties (or, equally, conventions) in international commerce is the United Nations Convention on Contracts for the International Sale of Goods. It was prepared by UNCITRAL and adopted in Vienna in 1980. In common parlance, the convention is referred to as the “Vienna Convention” and in publications often abbreviated as “CISG”.
The CISG is a success. Considering the number of ratifications, the Vienna Convention is a great success. The text has been ratified by over 75 countries worldwide. Important countries that have not (yet) ratified the CISG include the UK, India, Portugal, South Africa and several countries in the Middle East. An up-to-date map can be found on or through the websites of uncitral and legacarta.net/maps.
Accessibility and supporting materials. The vienna convention has been translated into the six official u.n. Languages, as well as (inter alia) into german, italian and portuguese. This makes the cisg widely accessible. Moreover, there is an abundance of materials explaining the scope and application of the Vienna Convention. a brief presentation is given below.
 U.N. Convention on Contracts for the International Sale of Goods, Vienna, 1 April 1980. It entered into force on 1 January 1988.
 Note that for the Convention to be applicable, it is sufficient that only one contracting party has its place of business in a contracting State and that the rules of private international law lead to the application of the law of a contracting State (Article 1).
 See in particular: Commentary on the Draft Convention for the International Sale of Goods, prepared by the Secretariat (document A/Conf.97/5), dated 14 March 1979, available at: www.cisg-online.ch.
Note: this chapter is also included in the e-book Cross-border contracting – How to draft and negotiate international commercial contracts, written by Weagree-founder Willem Wiggers and published by the ITC (the joint agency of the U.N. and WTO) and downloadable free of charge.