The history of the American West has usually been seen from the perspective of American expansion. Drawing on previously unexplored primary sources, James E. Officer has now produced a major work that traces the Hispanic roots of southern Arizona and northern Sonora—one which presents the Spanish and Mexican rather than Anglo point of view. Officer records the Hispanic presence from the earliest efforts at colonization on Spain's northwestern frontier through the Spanish and Mexican years of rule, thus providing a unique reference on Southwestern history.

The heart of the work centers on the early nineteenth century. It explores subjects such as the constant threat posed by hostile Apaches, government intrigue and revolution in Sonora and the provincias internas, and patterns of land ownership in villages such as Tucson and Tubac. Also covered are the origins of land grants in present-day southern Arizona and the invasion of southern Arizona by American "49ers" as seen from the Mexican point of view. Officer traces kinship ties of several elite families who ruled the frontier province over many generations—men and women whose descendants remain influential in Sonora and Arizona today.