Environmental Management Systems (EMSs) offer an approach to regulatory policy that lies somewhere between free-market and traditional command-and-control methods. Worldwide, hundreds of thousands of private firms have adopted or are considering adopting these internally managed systems for improving environmental performance. In the United States, the Environmental Protection Agency has established a special recognition for firms that adopt EMSs. Already, numerous state agencies have proposed or adopted 'green-tier systems' that allow firms with EMSs to be exempted from otherwise applicable requirements. Yet while private- and public-sector interest in EMSs is booming, limited empirical evidence is available about the efficacy of EMSs. To close the gap between advocacy and analysis, Regulating from the Inside brings together cutting-edge work of leading scholars, providing the most comprehensive analysis to date of environmental management systems. Intended to frame the future policy and the research agenda about EMSs, the discussions are organized around two critical questions: How have EMSs worked in firms that have already adopted them? What potential and limitations do they have as policy tools in the future? Addressing the arguments of both advocates and skeptics, the chapters examine why firms adopt EMSs; how firms implement EMSs; how EMSs answer concerns about fairness, corporate social responsibility, and sustainability; and what kind of impact EMSs may have on the global economy.