Official National Park illustrated handbook chronicles how the land between the Mississippi River and the Pacific Ocean was explored, mapped, photographed, and settled between 1803 and 1879. Part one includes a brief historical narrative of the events that lured men westward between 1803-1879. Part two describes the mountain men, explorers and scientists who helped in the western expansion to the Pacific Ocean. Part three is a documented pictorial record created by artists, cartographers, and photographers who accompanied the organized expeditions to the west.