Traditionally, economic analysis treats the economic system as one of the givens. The term "design" in the title is meant to stress that the structure of the economic system is to be regarded as an unknown. An unknown in what problem? Typically that of finding a system that would be, in a sense to be specified, superior to the existing one. The idea of searching for a better system is at least as ancient as Plato's Republic, but it is only recently that tools have become available for a systematic, analytical approach to such search procedures. This new approach refuses to accept the institutional status quo of a particular time and place as the only legitimate object of interest and yet recognizes constraints that disqualify naive Utopias.