Bannon writes haphazardly and with no structure whatsoever, all he seems to be concerned with is filling the pages of his borderland history with insignificant missionary characters who play little part in the development of the Spanish frontier. The book is boring and very disjointed and difficult to read.

As one of the volumes in the Holt, Rinehart and Winston "Histories of the American Frontier" series, this work provides an extensive look at Spanish expansion and activities in what was called by Herbert Eugene Bolton, The Spanish Borderlands, from the 1513 landing of Juan Ponce de León in Florida, to Mexican Independence in 1821. Utilizing an extensive array of primary and secondary source materials, he traces the history of Spanish northward movement out of Aztec Mexico in three separate pronged movements in time-one up the West coast of Mexico; the second up through what is now New Mexico and the last into Texas. He essentially points out a difference between Anglo-American approaches and the Spanish, seeing the areas of Texas, New Mexico, Arizona and California which are presented as basically defensive enclaves, especially after the late 18th century. Importantly, those that moved north into what later became part of the United States did not enjoy the overall freedom that their counterparts further north later enjoyed. A basic thesis is that Spain did not allow the "rugged individualism" so notably applicable to the Anglo-Americans. Initially motivated by avarice, the Conquistador's explored great portions of areas now incorporated into the United States. Nonetheless, after 1543, the Spanish were driven more by a genuine religious concern for Amerindians, influenced greatly by the Franciscan and Dominicans, and somewhat the Jesuits. Hence, using the mission church to convert and pacify Indians, the presidio became a support to an essentially religious motive with a civil end-for which they were quite successful until they met the nomadic Indians from the Plains. Bannon's narrative, at times, seems overburdened with details and names, but this is the nature of historical writing. Overall, this book will be more appreciated by those already possessing a good knowledge of American history; in the end, Bannon effectively carried on the work of his mentor, Bolton, providing a more complete look at a part of history that has been essentially overlooked