The title of this book reflects the enormous changes that have occurred in the legal regulation of public purchasing in the 1990's. These changes have two main drivers. The first is the implementation of national reform programmes in public procurement, especially in developing countries and those countries making the transition from planned to market economies, which have been encouraged by international institutions such as the World Bank and UNCITRAL. The second is the efforts that have been made to open up government procurement markets to international trade, both through regional agreements and globally through the World Trade Organization. These agreements have required many states to modify their national procurement rules or to introduce regulation in procurement for the first time.