Lieutenant Jose Cortes of the Spanish Royal Corps of Engineers was a keen observer of the native peoples of the Northern Borderlands of New Spain. Especially fascinated by the Apaches whom he observed at frontier presidios in the 1790s, he gleaned all possible information from veterans of the frontier service, and in the process grew from sympathetic inquirer to virtual advocate. Recognizing the strategic importance not only of the Apacheria but also of Indian peoples in the farthest reaches of New Spain, the zealous officer combed available archives, summarizing data reported over a...