This chapter argues that Toxics Release Inventory (TRI) is a watershed, pioneering the systematic use of performance monitoring and benchmarking as regulatory tools. It examines a series of interlocking and mutually reinforcing explanations of TRI’s operative success. The chapter argues that TRI works by creating a transparent and information-rich environment in which internal and external monitors are better able to evaluate and track performance, demand improvements, and hold managers accountable. It examines some of TRI’s shortcomings and limitations, both those that may be corrigible within the TRI framework, and those that suggest deeper and more general limitations on the use of performance monitoring and benchmarking as regulatory tools. Environmental Protection Agency (EPA) has also launched a number of environmental quality monitoring systems under the “right-to-know” rubric. EPA should continue to refine TRI through an accelerated program to periodically add or delete listed toxic pollutants based on the best currently available science.