Overview of the book "North Frontier of New Spain"

The book "The North Frontier of New Spain" has caught my attention of late. I have heard good things about it, but seeing the price tag ($90, used hardcover) makes me consider whether to purchase or to read within a local library. Before making my decision, I need to know exactly what type of information is in the book. I especially need to know the level of detail with which the southeast outskirts of Nueva Galicia are covered. Suggestions on buying or reading are also appreciated.

Jesús Rodriguez Gamboa