The quarter-century of Mexican sovereignty over the land that is today the American Southwest was a period of turmoil and transition. Between 1821 and 1846, Mexico City's ties to the far northern frontier were steadily weakened by domestic political and social strife as well as by foreign economic encroachment. The gradual loss of social and economic links and the eventual lapse of political allegiance is perceptively reinterpreted from the Mexican perspective by Professor Weber.

The book is essential reading for all who are interested in the history of the West and the Southwest. The late Ray Allen Billington praised the book as "meticulously prepared, sparklingly written, and brilliantly interpreted. Its perspective will affect all writing on western history for a generation to come."