Book excerpt: Biodiversity loss is one of the major resource problems facing the world, and the policy options available are restricted by inappropriate economic tools which fail to capture the value of species and their variety. This study describes in non-technical terms how cost-benefit analysis techniques can be applied to species and species loss, and how they provide a measure of the efficiency of conservation measures. Only when conservation can be shown to pass such a basic economic test, the authors claim, will it be incorporated into policies.;David Pearce has also written Blueprint for a Green Economy.