Markets are at the heart of our economy.  But markets are not always organized around a Walrasian auctioneer, and there are generally good reasons for that.  In other words, the organization of markets should not be taken as given, as it emerges from the needs of market participants given the imperfections of the economy in which they live.   As a consequence, market regulations not only affect the strategies that market participants adopt, but also induce changes in the way the market itself is organized.  So it is important to understand the drivers of the structure and organization of markets.  The purpose of this conference is to bring together leading scholars to present and discuss current work on the organization of markets.  The conference organizers are Cyril Monnet, Senior Economic Advisor at the Federal Reserve Bank of Philadelphia, Guillaume Rocheteau, Professor of Economics at the University of California at Irvine, and Peter Rupert, Professor of Economics at the University of California at Santa Barbara.