In 1850 St. Louis was the commercial capital of the West. By 1860, however, Chicago had supplanted St. Louis and became the great metropolis of the region. This book explains the rapid ascent and the abrupt collapse of the Missouri city. It devotes particular attention to the ways in which northeastern merchants fueled the rise of St. Louis. But unlike most studies of nineteenth-century cities, the book analyzes the influence of national politics on urbanization. It examines the process through which the sectional crisis transformed the role of Yankee merchants in St. Louis's development and thus triggered the fall of the first great city of the trans-Mississippi West.