From 1784 to 1812, fur trader, surveyor, and mapmaker David Thompson explored western North America. His field journals provide the earliest written accounts of the natural history and indigenous cultures of what is now British Columbia, Alberta, Montana, Idaho, Washington, and Oregon. Thompson was the first person to fully chart the Columbia River, and his wilderness expeditions have become legendary. Jack Nisbet tracks the explorer across the continent, interweaving his own sharp observations with Thompson’s historical writings.