In 1968, Sveriges Riksbank (Sweden's central bank) established the Prize in Economic Sciences in Memory of Alfred Nobel, founder of the Nobel Prize. The Prize in Economic Sciences is awarded by the Royal Swedish Academy of Sciences, Stockholm, according to the same principles as for the Nobel Prizes that have been awarded since 1901. This volume is a collection of the Nobel lectures delivered by the prizewinners, together with their biographies and the presentation speeches, for the period 2006-2010.List of prizewinners and their award citations:(2006) Edmund S Phelps — for his analysis of intertemporal tradeoffs in macroeconomic policy;(2007) Leonid Hurwicz, Eric S Maskin and Roger B Myerson — for having laid the foundations of mechanism design theory;(2008) Paul Krugman — for his analysis of trade patterns and location of economic activity;(2009) Elinor Ostrom — for her analysis of economic governance, especially the commons, and Oliver E Williamson — for his analysis of economic governance, especially the boundaries of the firm;(2010) Peter A Diamond, Dale T Mortensen and Christopher A Pissarides — for their analysis of markets with search frictions.