Ecosystem services can be broadly defined as the aspects of ecosystems that provide benefits to people. The aim of this book is to provide guidance on the valuation of ecosystem services, using the case of multi-functional wetlands to illustrate and make recommendations regarding the methods and techniques that can be applied to appraise management options. It provides a review of ecosystem service valuation rationale, including its importance from both a policy and project appraisal perspective, and a useful reference when considering policy and appraisal of ecosystem management options. It shows how legal obligations and other high-level management targets should be taken into account in valuation exercises, thus giving important policy context to the management options. The authors argue that it is not only ecosystems themselves that should be valued but also the goods and services provided, which affect human welfare. They build upon the idea of ecosystem services as the aspects of ecosystems consumed or utilized to produce human well-being, thus including ecosystem organization (structure), operation (process) and outflows. They set out what they call an Ecosystem Services Approach to the full appraisal of the role of ecosystem services in the economy and society. Although concentrating on wetlands, the approaches suggested provide an assessment framework, which can be applied, to other types of ecosystem assets.