Voluntary approaches to environmental policy, including agreements negotiated with industry on environmental performance and public programmes in which companies can voluntarily participate, are becoming increasingly popular in a number of countries. However, the OECD`s work questions its environmental effectiveness and economic efficiency. Voluntary Approaches for Environmental Policy: Effectiveness, Efficiency and Use in Policy Mixes provides an in-depth assessment of the use of voluntary approaches, drawing on a series of new case studies and extensive research into the available literature. The analysis focuses both on voluntary approaches, which are used in isolation, as well as in the context of policy combinations. As resources for voluntary action continue to grow, a question must be asked about the factors that influence compliance with a voluntary agreement as an instrument of environmental policy. .