The distinctive contribution of this book is that it presents a pragmatic approach for preserving biological diversity.  Experts in a wide variety of fields, including philosophy, environmental policy, law, economics and biology, present different perspectives on how to prevent widespread extinction around the world.  Several chapters deal with basic questions such as how we should define biodiversity and how we should determine what is most important to save.  Two chapters focus on how we can place an economic value on biological diversity, a step that is often critical for gaining acceptance for conservation efforts.  One of the major conclusions is that people are often willing to pay to preserve natural systems that have no immediate value in terms of generating income or commodities.  Other chapters are case studies of efforts to protect particular species or ecosystems; these provide practical guidelines for how to protect biodiversity more effectively.