For class planning purposes, instructors may find a brief list of changes from the previous edition of Environmental Law and Policy here. The sixth edition of Environmental Law, and Policy: Nature, Law, and Society continues a five-decades-long history that stresses the background theme of citizen participation and enforcement of environmental protection laws originally championed by Professor Joseph L. Sax. This text was and remains a pioneering book, having been the first environmental protection law book to apply the "taxonomic" approach and couple it with a focus on citizen action to protect and enhance the environment. Designed to be teachable at several different educational levels, this book is suitable for and has been used in law schools, graduate environmental studies programs, and even in undergraduate classes. The book's approach is to explore different models of structural designs of regulation, usually stressing a particular regulatory technique in the medium setting that best exemplifies its application. For example, the harm-based ambient standards began and are best illustrated by the operation of State Implementation Plans under the Clean Air Act. Over time, most of the statutes have expanded to include more than one taxonomic feature, but by isolating differing regulatory mechanisms, students learn to assess the advantages, disadvantages, and practicalities of different structural approaches, so they can engage, analyze, and understand any regulatory system in whatever legal setting they thereafter encounter. As a new feature, the sixth edition offers two subject-area-focused chapters, one on oceans and one on energy and climate change. Perhaps most importantly, this sixth edition was delayed a few months to provide a better sense of what the second Trump Administration is doing to alter environmental protection law. The field faces unprecedented governance turmoil. This new edition of the book explores how environmental protection and the rule of law have been undergoing attack, with an eye toward conserving, restoring, and advancing the protections developed in a demanding bipartisan evolutionary process over the past half century. As in previous editions, this casebook is designed to be flexible, so that professors can select sections that reflect their own teaching or scholarly interests. Zygmunt Plater is Emeritus Professor of Law at Boston College Law School. Eric Hull is a Professor of Law at Nova Southeastern University Shepard Broad College of Law. Robert Abrams is a Professor of Law at Florida A&M University. Robert Graham is Of Counsel at Jenner & Block Law Firm. Noah Hall is a Professor of Law at Wayne State University Law School.