The search for 'smarter' ways to prevent or control pollution has generated heated debate on almost every conceivable topic related to setting goals, improving institutional arrangements, and choosing the most effective means for achieving those goals. This last issue choosing the means or policy instruments to meet environmental goals can be a surprisingly complex task for decision makers, given the need to balance other competing concerns. The environmental policy toolbox contains many and varied instruments but lacks a clear set of instructions for their use. This OTA report fills that need. The 'guide' is organized into three major sections: (1) The Environmental Policy Toolbox: a discussion of 12 major policy tools, their frequency of use, and key strengths and weaknesses. (2) The Criteria for Comparing Tools: our evaluation of how effective these instruments are in achieving the values and interests or criteria decision makers are likely to weigh. (3) Choosing Tools: a series of questions for matching a tool or tools to a specific problem. Choosing tools that satisfy several, much less all, of these criteria for a specific problem is the challenge. Unfortunately, no perfect policy tool exists to meet everyone's expectations for every problem.