This is a heavily-annotated Ph.D dissertation transformed into a readable history. The book is really the story of the Arizona-Sonora border. Truett’s focus is on the 1890s shifting of America’s westward expansion southward into Mexico. The author calls this the Southwest’s “hidden history,” tying in silver’s John R. Bartlett to copper’s William Cornell Greene, and, finally, after 1911, to revolutionaries like Villa and Obregon, who made the Borderlands a battleground. This is the story of a near-erasure of the border between U.S. and Mexico—the transformation of a desert barrier into a crossroads of economic activity.