Kenneth Mills sets out to freshen the extensive literature on Peru’s “extirpation of idolatries” by treating orthodox and “idolatrous” religious practices as interpenetrating, coevolving traditions—in other words, by questioning the “self/other” boundary the sources presuppose. He also inverts common assumptions about “crucial” periods. Much literature concentrates on the earlier campaigns. Extirpation lashed indigenous parishes of the Archbishopric of Lima from 1609 to 1621, gained renewed force in 1625-26, and, after a quiescence, surged again from 1646 onward under the guidance of Archbishop Pedro de Villagómez (1640-71), who is Mills’ leading protagonist. Pioneer historians of extirpation saw post-Villagómez prosecutions—up to 1750—as the slow death of an increasingly irrelevant institution. Mills thinks the neglected late phases reveal a situation different from the earlier one and at least as important to changing rural ways of life.

Unlike their precursors up to the 1620s, who construed huaca devotions as a rival “faith,” or at least a mind-set to be answered in its own terms, late visitadores considered Andean worship an incoherent hash of Satanic errors, superstitious trivia, and garbled Catholicism—“not even wrong,” as Wolfgang Pauli said of bad physics.

Despite inflammatory talk about paganism, however, late visitas were not really a matter of corralling infidels. Rather, extirpation responded to “serious imperfections in the Christianization process” already realized (p. 172). For this reason, Mills rightly holds extirpation to be an outlying battlefield of the European Catholic reformation. (He could have noted that Villagómez’s visitador, Bartolomé Jurado, translated Roberto Bellarmino into Quechua.) The struggle was never about whether Peru would become Christian. It was about the way some thought Peru should have become Christian, as opposed to the “disturbingly ambiguous” way it had already done so. Like Shining Path rebels of the 1980s, extirpators sought to force the clock backward and do history over again by the utopian book (in this case, the Archdiocese’s conciliar books, which curates were required to own).

However, in Peru, unlike Europe, “reform” seized on the idea that error was an inborn propensity of certain peoples. Extirpation’s long-term contribution to the racialization of the orthodox/heterodox distinction proved as durable as its pastoral efforts proved futile, a facet that deserves greater emphasis.

Thus far, one might take the “crystallization” (Manuel Marzal’s term) of a distinctive unofficial Christianity as the bottom line. But in his penultimate chapter, Mills argues that religious change has no holistic endpoints. If “Colonial Andean Religion” means anything, it means a mode of continuous innovation, not a hidden creed. Myriad individuals’ half-conscious choices of “eclectic, even experimental … solutions to life’s problems” (p. 251) were the sum and substance of it.

Mills’s argument marks a great and welcome improvement over the “clash of faiths” model. To readers familiar with the actual grain of the trials, it will ring true. Three early chapters reconstructing rural religious practice bring forward persons usually lost in the middle-distance blur of ethnographic generalization, and this too is powerful material. The book will richly satisfy those who inquire into religion as such. However, researchers oriented to socioeconomic issues will find Mills less interested in nonreligious factors than many other researchers. The subdued sociological light verges on obscurity where the urban component is concerned. One would not guess from this book that some late cases involved indigenous or Afro-indigenous urbanites who lived just steps from the Cathedral. Surely these matter for a model of coevolving orthodoxy and heterodoxy. Similarly, social historians may note a lack of statistics about idolatry cases (by decade, gender, etc.).

Mills vibrantly succeeds in guiding the reader through the terrain of clandestine religious pluralism. A work of impressive erudition, his book brings Andean historiography a long step closer to rediscovering the neglected “colonial middle” (p.12) as an era during which Quechua- and Aymara-speaking peoples became actors in transatlantic early modern history.