This volume reports key findings of the Biodiversity Program of the Royal Swedish Academy of Sciences' Beijer Institute. The program brought together a number of eminent ecologists and economists to consider the nature and significance of the biodiversity problem. In encouraging collaborative work between these closely related disciplines it sought to shed new light on the concept of diversity; the implications of biological diversity for the functioning of ecosystems; the driving forces behind biodiversity loss; and the options for promoting biodiversity conservation. The results of the program are surprising. It is shown that the core of the biodiversity problem is a loss of ecosystem resilience and the insurance it provides against the uncertain environmental effects of economic and population growth. This is as much a local as a global problem, implying that biodiversity conservation offers benefits that are as much local as global. The solutions as well as the causes of biodiversity loss lie in incentives to local users.