Tamra B. Orr & Xina M. Uhl 
Primary Source Investigation of the Lewis and Clark Expedition [PDF ebook] 

President Thomas Jefferson’s Louisiana Purchase added about 828, 000 square miles of unmapped, unknown land to the young United States. To explore and map this great swath of land, Jefferson sent Meriwether Lewis, William Clark, and their Corps of Discovery to brave rivers, plains, and mountains. They met American Indians both friendly and hostile, discovered dozens of previously unknown species, and carved for themselves an enduring place in American history. Complete with maps, excerpts from Lewis and Clark’s journals, and images of artifacts, this volume tells a timeless tale of adventure, hardship, and triumph.