This compilation article provides a rare behind the scenes glimpse into landmark environmental cases from those who litigated them, including Robert F. Kennedy, Jr., Bruce Terris, Professor Zygmunt Plater, Professor Ann Powers, Mike Axline, David Bookbinder, and Peter Lehner. In 1970, Congress gave citizens the remarkable authority to file federal lawsuits as “private attorneys general” to enforce the Clean Air Act (CAA). Congress intended citizen suits to fill the vast void left by inadequate enforcement by federal and state regulators, and to ensure compliance and deter illegal activity. The approach stuck. Now more than one dozen federal environmental statutes, numerous state laws, and myriad foreign laws allow for such “environmental citizen suits.” To commemorate the inception of the first environmental citizen suits, on April 4, 2003, the Widener Law Symposium Journal and the Mid-Atlantic Environmental Law Center, joined by co-sponsors the Environmental Law Reporter, Sierra Club, and Trial Lawyers for Public Justice, hosted a conference at the University’s campus in Wilmington, Delaware, Environmental Citizen Suits at Thirtysomething: A Celebration and Summit. The conference featured a virtual who’s who of leading environmental Law lawyer advocates and law professors. At its core, the compilation is a clarion call for citizen action, and informs how citizen suits propagate democracy, provide appropriate economic feedback to the marketplace, and help make the world a better place for rivers, plants, animals, people of all walks, and generations to come.