Alexander was the first man; in the known history who established the first supply line for the business form Macedon to India. Then they were Mongols; who clear the whole road for business from Baghdad to China. Accordingly international business is not a new concept for the world that just came with WTO (World Trade Organization). However 16th century Adim Smith's theory of "Absolute Advantage" gave a boost to trade internationally for import those things that u can't make efficiently and export those goods that no one can make efficiently other then yourself. Recado came up with a new idea for the international trade that not just on absolute advantage also keep in mind the "Comparative Advantage", that u can gain to sale those goods in which u r best according to your productivity.
Beyond the theories, breakthrough inventions made information and even transfer of physical goods so easy than ever. From Japan to United State anything can reach in less than 24 hours and information from the same place to all over the world in even less than second. These inventions reduce the differences between countries and boundaries are becoming blurred. China can sell its product in all over the world. Pakistan can get maximum reward for the best quality cotton and also can buy cheap Japanese cars even in Pakistan. In the long run free trade is best in country interest.