In this policy symposium, Resources For the Future (RFF) experts shed light on whether markets are the right tool to fix the nation's environmental ills. Over the past 60 years, regulators have implemented market based programs for air pollution, water pollution, land management, and other environmental policy problems at local, state, federal, and -- in the case of greenhouse gas regulation -- international levels. Some applications hew more closely than others to ideal market-based policy design, as defined by economic theory, and programs have met with varying degrees of success. In this symposium, drawn from discussions at RFF's December 2012 First Wednesday Seminar, four RFF scholars draw lessons from the successes -- of which there have been few -- and the many failures. They also consider the desirability, feasibility, and design of market-based environmental policy in the future.