Description Merriwether Lewis and William Clark were chosen by President Thomas Jefferson to explore the newly purchased Louisiana Territory. Readers look at the highs and lows of the Voyage of Discovery, and the roles played by the people who joined them. They will learn how first-hand accounts from journals provide primary source knowledge of this adventure, as well as how different people approach the same event from different perspectives. Paintings, photographs, and maps present the huge scope of this trek, and explain how important the journey was to America's westward expansion.