When early Spanish explorers accidentally released wild horses (Equus cabalus) to the continent in the early 1500s, they returned an American original. Although the remnants of the escaped Spanish horse are protected by the 1971 Free-Roaming Wild Horse and Burro Act, each year thousands are removed from public lands across the American West to reduce competition between horses and domestic livestock. El Caballo documents one of the most complex wildlife management issues today. Where do modern wild horses fit in our view of the natural world?