This account of the Lewis and Clark Expedition, published in 1814, is based on the detailed journals kept by Captains Meriwether Lewis and William Clark, the leaders of expedition. The book begins with “Life of Captain Lewis,” written by Thomas Jefferson, which reproduces Jefferson’s detailed instructions to Lewis regarding the goals of the expedition. “The object of your mission is to explore the Missouri River, and such principal streams of it, as, by its course and communication with the waters of the Pacific Ocean, whether the Columbia, Oregan [sic], Colorado, or any other river, may offer the most direct and practicable water communication across the continent, for purposes of commerce.” The 29-man Corps of Discovery set out from St. Louis on May 14, 1804. In the next 28 months, Lewis and Clark traveled more than 12,000 kilometers through unfamiliar terrain inhabited by Indian tribes. By the end of 1804, they had made it to the Great Bend of the Missouri River. In 1805, they journeyed up the Missouri, across the Rocky Mountains, and down the Columbia River to the Pacific Ocean. After suffering through a dismal winter, the members of the expedition began their long return journey, finally reaching Saint Louis on September 23, 1806.