Investment projects are increasingly designed to provide multiple benefits. Some of these benefits are easily quantified through market-valuation methods while others are measured for their nonmarket values. The contingent valuation method (CVM) is one of the most widely used techniques to quantify and value benefits from nonmarket goods and services, such as improvement in air and water quality, and protection of ecosystems. This reference book provides a comprehensive guide to CVM. It aims to help improve future CVM studies and estimation of willingness to pay to inform economic analysis at the Asian Development Bank and beyond.