"Undaunted Courage" by Stephen E. Ambrose is a non-fiction historical account of the Lewis and Clark expedition to explore and map the western portion of the United States in the early 19th century. The book covers the preparations for the expedition, the challenges and dangers faced by the Corps of Discovery, their interactions with Native American tribes, and their eventual successful return to St. Louis. Ambrose draws extensively on primary sources, including the journals of Lewis and Clark, to provide a detailed and engaging narrative of this landmark expedition. The book offers insights into the personalities and motivations of the explorers, as well as the historical context of the time period. Overall, "Undaunted Courage" is a fascinating and well-researched account of one of the most important journeys in American history.