Hayduke is an ex-Green Beret, one-time explosives expert and medic in the Vietnam War; and an American environmentalist hero.
The character of Hayduke was based on his friend and author, Doug Peacock, a Vietnam vet that Abbey befriended and traveled with in the Southwest United States.
The adventures of Hayduke and the original Monkey Wrench Gang become tied with the activities of more legitimate environmental organizations like Earth First!.
George Hayduke uses a number of aliases over the course of the books, including: Leopold, Rudolf the Red, Herman Smith, Fred Goodsell, Crazy Horse.
Hayduke states that Edward Abbey was his mentor and says The Monkey Wrench Gang inspired the founding of Earth First!.