Journey with the early American explorers who helped to encourage the western expansion of our new nation. The life stories of the men who explored, mapped, and studied the frontier west of the Mississippi River are narrated in this lively series about discovery and adventure. Each book includes period illustrations and photographs, maps, a timeline, and a list of primary sources. Written sources, such as journals and diaries, and visual sources from the time period will help students learn about the historical development of the United States.