University of Delaware environmental historian Adam Rome has been teaching Earth Day for years, but when he looked into its origins, he was surprised by the scant documentation. In The Genius of Earth Day, Rome explores how modern environmentalism began—gathering the strands of conservationism and the nature nostalgia of the counterculture under a mass movement inspired by the upheavals of the 1960s, yet guided by an Establishment figure, Wisconsin Senator Gaylord Nelson. Rome attributes the enduring success of Earth Day to its dual essence as “an educational experience as well as a political demonstration.” As a result, pollution became political and growing numbers of Americans became conscious of themselves as part of the environment, not lords of it.