I just finished reading a great book called Sources of the River: Tracking David Thompson Across Western North America. If you are into reading such books about early American explorers (and I use American in the North American sense) such as Lewis and Clark, I would recommend this book. Nisbet is a good storyteller, and without going into 500 pages of detail, gives you a good picture of what life was like for Thompson in a land that no white man had ever seen.
David Thompson came to America as a 14 year old in 1784, to begin an internship for the Hudson Bay trading company. He learned to operate trading posts and the transport of furs up and down the Saskatchewan river. He had a knack for mathematics and turned out to be a fantastic navigator. His surveys and notes of the upper Missouri region were used by Lewis and Clark on their expedition to the Pacific Ocean after the turn of the century.
By the time he was 30, Thompson was leading the way for fur trappers over the Rockies. Just a few years after Lewis and Clark found their way back to the Mississippi, Thompson led an expedition to chart the entire course of the Columbia River in an attempt to find an avenue for the fur trade to the Pacific (going over the Continental Divide was a right pain). Upon retiring, he drew up some of the best maps of the Northwest from that time period, utilizing his measurements and notes, Lewis and Clark’s notes, and information from the native tribes.
You also get an interesting look into the native tribes in that region. Thompson and the fur trappers spent considerable time (years) interacting and trading with native Americans on both sides of the mountains.
Give yourself a look-see into the life of men who never walked down city streets, or rarely saw another white man for months on end.
Undaunted Courage, the story of Meriwether Lewis by Stephen Ambrose, is also a great book detailing the life of an explorer we’re more familiar with. I would recommend both, side by side, as they complement each other.