When the first dinosaurs were discovered in the Wild West, it led to one of the greatest scientific battles in American history. With Indian wars swirling around them, Edward Drinker Cope and Othniel Charles Marsh conducted their own personal warfare, staking out territories, employing scouts, troops, and spies. Opposites in personality, background, and scientific beliefs, they symbolized the end of one era and the beginning of another, in politics as well as science. Cope, a Philadelphia Quaker, was an old-fashioned naturalist from a wealthy family. Marsh, a farm boy who had risen to a Yale professorship, was the very model of a modern scientific entrepreneur. Spurred on by James Gordon Bennett, the sociopathic publisher of the New York Herald, they drove each other to ruin, and the repercussions of their feud linger in the radical militias and terrorism of the West today.