The Character and Influence of the Indian Trade in Wisconsin, a study of the trading post as an institution

Classic work of American history. According to Wikipedia: "Frederick Jackson Turner (November 14, 1861 - March 14, 1932) is widely regarded, along with Charles A. Beard, as one of the two most influential American historians of the early 20th century. He is best known for The Significance of the Frontier in American History."