In a neoclassical world the existence of non-zero transaction costs, nonconvex technologies, public goods and so on creates inefficiencies which can be dealt with by various institutions. But, institutions can create inefficiencies of their own. This volume addresses the issue of efficiency and institutions from different angles. First, the efficiency of modern welfare states is analyzed on a general level where topics like social justice, redistribution and rent seeking are studied in an environment of pressure groups and self-interested politicians (papers by Streit, Schlieper, WickstrAm). Second, several papers deal with more specific issues like intergenerational transfers in a social insurance system, the efficiency of law, and contractual arrangements in the labor market (Witt, Rowley and Brough, Monissen and Wenger). Third, allocation procedures for nonexclusive public goods are analyzed (GA1/4th and Hellwig, Pethig).