Today we take for granted the idea that dinosaurs once roamed the earth. But two hundred years ago, the very concept of an extinct species did not exist. When an English scientist proposed in 1841 that ("terrible lizards") had come and gone, it was only a theory, a new way of explaining the "dragon" and "giant" bones scattered across the globe. But when proof turned up seventeen years later, it was not only incontrovertible; it was massive. tells the story of the feverish race between two brilliant, driven, and insanely competitive scientists—Edward Drinker Cope and Othniel Charles Marsh—to uncover more and more monstrous fossils in the newly opened Wild West. Between them, they discovered dozens of major dinosaur species and established the new discipline of paleontology in America. But their bitter thirty-year rivalry—a "war" waged on wild plains and mountains, in tabloid newsprint, and in Congress—dramatically wrecked their professional and private lives even as it brought alive for the public a vanished prehistoric world.