Robert Campbell (1804-1879) came to America from Ireland in 1822 and entered the fur trade soon thereafter. He quickly rose from trapper to brigade leader to partner, all within a half dozen years. In the mid-1830s, Campbell retired from the mountains, having already amassed considerable wealth, and embarked on a new career. He returned to St. Louis and built up a business empire that embraced mercantile, steamboat, railroad, and banking interests. Through these ventures he not only gained more wealth but also became a leading force behind the development of the region's economy. Exploring the enormous treasure trove of letters, journals, and account books that Campbell left behind, William Nester places Campbell in the context of the times in which he lived, showing the economic, political, social, and cultural forces that provided the opportunities and challenges that shaped his life.