August 2011 is the 40th anniversary of the suspension of gold convertibility of the dollar by President Nixon, which brought the Bretton Woods system of fixed exchange rates to an end. There are several lessons to be drawn from the experience during this period. One seems to be that you need a hegemonic power or a binding agreement whereby countries commit themselves to follow certain clear rules of the game to operate an international monetary system; in the past 40 years we have had neither