On Earth Day 1970 20 million Americans displayed their commitment to a clean environment. It was called the largest demonstration in human history, and it permanently changed the nation's political agenda. By Earth Day 2000 participation had exploded to 500 million people in 167 countries. The seemingly simple idea—a day set aside to focus on protecting our natural environment—was the brainchild of U.S. Senator Gaylord Nelson of Wisconsin. It accomplished, far beyond his expectations, his lifelong goal of putting the environment onto the nation's and the world's political agendas.

A remarkable man, Nelson ranks as one of history's leading environmentalists. He also played a major role as an early, outspoken opponent of the Vietnam War, and as a senate insider was a key player in civil rights, poverty, civil liberties and consumer protection issues. The life of Nelson, a small town boy who learned his values and progressive political principles at an early age, is woven through the political history of the twentieth century. Nelson's story intersects at times with Fighting Bob La Follette, Joe McCarthy, and Bill Proxmire in Wisconsin, and with George McGovern, Lyndon Johnson, Hubert Humphrey, Russell Long, Walter Mondale, John F. Kennedy, and others on the national scene.