The set of eight papers in this book undertake a rigorous empirical analysis of the intended and unintended economic welfare effects of agricultural and biotechnology policies in the United States, focusing on agricultural price subsidies, federal crop insurance programmes and mandates for promoting the use of biofuels. The application of new empirical methods to carefully assembled new data sets is a key feature of this book. The major contribution is that it highlights the diversity and incredible complexity of government interventions in almost all conceivable aspects of agricultural markets in the United States – including farm production, prices, land use, environmental quality, food consumption and safety and insurance. The sheer pervasiveness of government interventions is at complete variance with the ‘free market’ paradigm that underpins policy discourse in the United States and emphatically dispels the economic textbook notions of agricultural markets being ‘unregulated’ or ‘perfectly competitive’. The unintended consequences of these policies, which derive from complex institutional arrangements, foster inefficiencies on a giant scale and redistribute welfare gains intended for producers to processors, landowners or insurers. The persistence of hugely market-distorting agricultural policies in the United States in the face of large-scale inefficiencies raises a number of questions about the determinants of policy. The political economy of agricultural policy and coalitions of special interest groups may account for the persistence of these policies – but it is a sobering thought that rigorous economic analysis appears to have a terribly weak influence on policy directions.