Book excerpt: One of the most controversial issues in environmental law and policy-and one that of considerable importance to the EPA-is the allocation of power and authority between the federal and state governments. The recent evolution in approaches of environmental enforcement highlights many of the tensions inherent in this debate. During the past several years, the federal and state governments have spent a good deal of energy attempting to "reinvent" their relationship. The shifts in federal/state enforcement relations are highly significant, with the potential to fundamentally reorder the division of authority that has existing over the past 25 years. This book thoroughly documents the changing nature of federal/state relations in enforcing environmental law. It breaks new ground in analyzing the federal/state enforcement relationship, particularly in light of the many recent developments that have occurred in this area. The author's findings provide important lessons about the interplay between federal and state efforts in other regulatory areas, and for the structure of federal/state relations generally. Professors Rechtschaffen's and Markell's clear, in-depth analysis will be essential reading for legal and regulatory experts, attorneys who are involved in environmental enforcement matters, the judiciary, legislators, political scientists, public policy experts, and anyone with an interest in environmental law and policy.