Environmental protection is now an integral part of public policies, at local, national and global levels. In all instances, the cost and benefits of policies and projects must be carefully weighed using a common monetary measuring rod. Yet, many different categories of benefits and cost must be evaluated, such as health impacts, property damage, ecosystem losses and other welfare effects. Furthermore, many of these benefits or damages occur over the long term, sometimes over several generations, or are irreversible (e.g. global warming, biodiversity losses). How can we evaluate these elements and give them a monetary value? How should we take into account impacts on future generations and of irreversible losses? How to deal with equity and sustainability issues? This book presents an in-depth assessment of the most recent conceptual and methodological developments in this area. It should provide a valuable reference and tool for environmental economists and policy analysts.