Over the last decade the regulatory evaluation of environmental and public hea lth risks has been one of the most legally controversial areas of contemporary government activity. Much of that debate has been understood as a conflict be tween those promoting 'scientific' approaches to risk evaluation and those pro moting 'democratic' approaches. This characterization of disputes has ignored the central roles of public administration and law in technological risk evalu ation. This is problematic because, as shown in this book, legal disputes over risk evaluation are disputes over administrative constitutionalism in that th ey are disputes over what role law should play in constituting and limiting th e power of administrative risk regulators. This is shown by five case studies taken from five different legal cultures: an analysis of the bifurcated role o f the Southwood Working Party in the UK BSE crisis; the development of doctrin es in relation to judicial review of risk evaluation in the US in the 1970s; t he interpretation of the precautionary principle by environmental courts and g eneralist tribunals carrying out merits review in Australia; the interpretatio n of the WTO Sanitary and Phytosanitary Agreement as part of the WTO dispute s ettlement process; and the interpretation of the precautionary principle in th e EU context. A strong argument is thus made for re-orienting the focus of sch olarship in this area.