Allocation of natural resources has become a prominent concern at the local, state, and federal level. Competing uses for increasingly scarce resources are requiring that the relative values of those uses be investigated. Although many types of value are important in decision making, this book is concerned with the economic value of natural resources. Economic values for certain natural resources are readily observable in markets. For others, however, market prices are not available, and estimates of value must be made through nonmarket valuation techniques. The progress that has been made in improving the theory, methods, and applications of these techniques has been remarkable. Along with the progress, however, come new problems that must be addressed. The chapters presented in this volume are a collection of examples of both progress and problems.