History has shown that openness to trade is a key ingredient for economic success and for improved living standards. But simply opening the economy to international trade is not enough. Developing countries – especially the least developed – require help in building their trade-related capacities in terms of information, policies, procedures, institutions and infrastructure, so as to compete effectively in the global economy. Aid for trade aims to help countries overcome the supply-side constraints that inhibit their ability to benefit from market access opportunities. The almost 300 case stories show clear results of how aid-for-trade programmes are helping developing countries to build human, institutional and infrastructure capacity to integrate into regional and global markets and to make good use of trade opportunities. Together, these stories are a rich and varied source of information on the results of aid for trade activities – an indication of the progress achieved by the Aid-for-Trade Initiative.