All societies depend on biodiversity and biological resources, and policy-makers are increasingly aware that development pressures are today generating unprecedented rates of biodiversity loss. The fact that biodiversity issues often receive low priority in policy decisions is at least in part due to problems involved in assessing its contribution to society -- these values defy easy description and quantification. What cannot be quantified, or is difficult to monitor and evaluate, is easy to disregard. The result is that biodiversity fails to compete on a level playing field in policy decisions with the forces driving their decline.

This Handbook describes the types of values usually associated with biodiversity. While there are exceptions to the need to prioritise economic values over other cultural, traditional and spiritual values, economic valuation has a sound theoretical foundation that can help clarify the tradeoffs implicit in public policy decisions. On the other hand, the Handbook recognises the limitations of the economic approach, and considers how economic and non-economic values can eventually be reconciled.

The Handbook also reviews the various methodological approaches often used to quantify these values. Data requirements and limitations are discussed. These methodologies are then applied to a series of concrete policy contexts, ranging from land use planning to the determination of legal damages for environmental degradation.