Snaking 2,540 miles from Montana to the Mississippi River, the Missouri is the longest waterway in the nation. Its basin--stretching 530,000 square miles--extends broadly into ten states and twenty-five Indian reservations. For millions of years the river and its tributaries meandered untamed. But that irrevocably changed with the passage of the Pick-Sloan Plan, part of the Flood Control Act of 1944.

In River of Promise, River of Peril, John Thorson takes the first comprehensive look at how and why the Missouri River basin-now with six major dams and hundreds of miles of navigation...