In the heart of North America, the Missouri, Ohio, and Mississippi rivers come together, uniting waters from west, north, and east on a journey to the south. This is the region that Stephen Aron calls the American Confluence. Aron's innovative book examines the history of that region -- a home to the Osage, a colony exploited by the French, a new frontier explored by Lewis and Clark -- and focuses on the region's transition from a place of overlapping borderlands to one of oppositional border states. A