This volume assesses the state of the art in applying economic valuation techniques to environmental problems in developing countries. It is in fulfilment of a contract between the United Nations Environment Programme (UNEP) and CSERGE, University College London. The volume outlines the available valuation techniques and surveys their application to developing country problems. It offers some guidelines and assesses the gaps in the available information. The general conclusions are that economic valuation is: a) Extremely useful in raising the profile of the environmental aspects of development projects and policies; b) Widespread in terms of its applications in developing countries; and c) Generally successful in its application.