The Great Plains
From Jim's list on western migration before the Civil War.
Originally published in 1932, this remains one of the most accessible and thought-provoking books ever written about the American West. Webb’s work rises to the level of literature, especially when describing early encounters by white Americans with the landscape and native people they met west of the 98th meridian. Few writers have captured so vividly the expansion of America from the humid and forested east to the arid west of the Great Plains. Some of Webb’s conclusions may feel a little dated, but this remains a very compelling and rewarding book.