In the 1880s, science witnessed a major shift: Charles Darwin proposed his theory of evolution. People dug up the first dinosaur fossils. And the field of paleontology—the study of ancient plants and animals—emerged. Othniel Charles Marsh and Edward Drinker Cope became enthralled with these new ideas, discoveries, and developments. Both were determined to become world-famous paleontologists. When they met in 1863, they started off as friends. But within a few years, competition drove the men apart. Each fought bitterly to discover more fossils, name more species, and publish more papers than the other. In their haste to outdo each other, they both produced some shoddy work. The resulting confusion took many years to discover and correct, and their toxic relationship crippled the field of paleontology for decades afterward. However, the competition also produced a wealth of fossils. These laid a firm foundation for the field of paleontology and supported Darwin''s theory of evolution. Marsh''s and Cope''s discoveries generated keen public interest in prehistoric life and rich data for future generations of paleontologists. This book explores the great rivalry between Marsh and Cope, showing how it brought out the best and the worst in them—while bringing humankind a brand-new view of life on Earth.