The westward drive of the warlike Sioux Indians along a thousand miles of prairie and woodland, from the upper reaches of the Mississippi to the lower Powder River in Montana, is one of the epic migrations of history. From about 1660 to the first quarter of the nineteenth century, the Teton Sioux swept away all opposition: Arikaras, Ponkas, Crees, Crows, Cheyennes--all fell away and dispersed as the Sioux advanced, until the invaders ranged over a...