Abstract
Why should governments or individuals invest time and resources in conserving biodiversity? A popular answer is that biodiversity has both instrumental value for humans and intrinsic value in its own right. Defending Biodiversity critically evaluates familiar arguments for these claims and finds that, at best, they provide good reasons for conserving particular species or regions. However, they fail to provide a strong justification for conserving biodiversity per se. Hence, either environmentalists must develop more compelling arguments for conserving biodiversity or else they should modify their agenda. This short precis is an overview of the central findings of our book.