His new book is The Yaquis and the Empire: Violence, Spanish Imperial Power, and Native Resilience in Colonial Mexico.
Here Folsom explains the connection of the book's cover to the pages within:
The cover of the book is an image of a Yaqui militia around the year 1910. For a variety of reasons, I think it is deeply significant for our understanding of the history of the Yaquis, the Spanish Empire, and Mexico. Most people who know anything about the Yaquis think of them as fierce rebels against the Mexican state, or as practitioners of ancient religions and “ways of knowing” described by the shaman-anthropologist-fantasist Carlos Castaneda. What my book shows is that neither of these images is accurate. For most of the colonial period, the Yaquis were staunch allies of the Spanish Empire, and came to embrace Catholic religious practice with great enthusiasm.Learn more about The Yaquis and the Empire: Violence, Spanish Imperial Power, and Native Resilience in Colonial Mexico at the Yale University Press website.
With the expansion of the Mexican state in the late 19th century, and increasing access to North American markets, the Yaquis’ river-bottom land became enormously valuable. When the Yaquis refused to vacate it, Mexicans convinced themselves that the Yaquis were incorrigible savages, rather than the creative, adaptive, politically savvy people they were. What we see in this image is Yaqui men prepared to fight alongside the Mexican soldiers standing behind them. There is enormous poignancy to this image because, to the untrained eye, it seems to confirm old stereotypes of Yaqui fierceness. But in reality, it tells the story of an enormously sophisticated people who were willing to defend their lands and customs by force, and yet were always open to alliances and dialogues with outsiders. The Yaquis had formed militias like the ones depicted here as early as the seventeenth century. This one was probably fighting alongside a faction of Mexican revolutionaries. The idea that the Yaquis were unbending rebels is an insult to their long record of intelligent, politic flexibility. Beyond that, I find the granular quality of the image, the way it fades to black at the edges, and the partially darkened faces of both Yaquis and Mexicans, to fit the darkness of the story I tell. It has a Cormac McCarthy-esque quality of depicting rugged frontier struggle and passion coexisting with mind-boggling depravity and violence.