In Bad Christians, New Spains, Byron Ellsworth Hamann has attempted an ambitious goal—comparing the experiences of Indigenous Mesoamericans and Spanish moriscos (descendants of Muslim converts to Christianity)—through a tightly focused monograph on two sets of Inquisition trials, one on each side of the Atlantic. Hamann analyzes these trials in dialogue to provide evidence of the interconnections across the Spanish empire in the sixteenth century. His focus on a “Mediterratlantic world” provides concrete examples of the global vision of early modern Spaniards, thus carrying forward the work of scholars such as Francisco Bethencourt and Kimberly Lynn on the Inquisition, Henry Kamen on Spain’s empire, and Sabine MacCormack on the legacy of antiquity in the early modern Spanish world. Hamann’s monograph contributes to the ongoing project of destabilizing the assumption that ideas, knowledge, and power flowed exclusively from the center to the periphery. He also highlights the ways in which relations between local authorities and minority populations were more complex than commonly imagined, building on the work of scholars such as James Tueller and Patrick O’Banion.His two microstudies are both focused in the 1540s. One set of trials took place in Oaxaca, located today in Mexico; while the other set of trials occurred in Valencia, Spain. Comparing these trials is productive, although at times Hamann underestimates the differences between the episcopal trials in Oaxaca (under the authority of the bishop and ultimately the Pope) and the Spanish Inquisition trials in Valencia (a state office under the authority of the inquisitor general and ultimately the king). Hamann rightly notes that the Spanish Inquisition was not established in New Spain until 1571, and in any event did not have the authority to try Indigenous people in the Americas—but the implications of this key difference between the experiences of Indigenous Americans and moriscos could have been considered in more detail throughout the monograph.Hamann begins his book with a brief introduction and a first chapter introducing his case studies, together with a broad overview of historiographical comparisons of Spanish interactions with Muslims and Native Americans. His second chapter maps out these two communities, introduces a summary of inquisitorial procedures, and establishes his analytical approach. From there, Hamann moves to the heart of his analysis, namely, a series of thematic chapters addressing the diversity of Catholic practices (chapter 3); material culture, particularly mosques and sculptures of Indigenous deities (chapter 4); iconoclastic violence (chapter 5); practices regarding the dead (chapter 6); and a discussion of various linguistic means of discussing time and the relationship between past, present, and future as a mechanism of exerting authority over subject populations (chapter 7). Chapter 5, “Ruination,” with its discussion of the destruction of mosques, “idols,” temples, and even clothing, emphasizes the experience of sacred violence and the relative importance of public practices rather than interior beliefs. Hamann also points out that by destroying these items and consigning them to the past, the destroyers also created something new, namely, the ruin, which continued to have an impact on surrounding communities. This is his most compelling chapter.Comparative transatlantic scholarship is complex and involves mastering multiple historiographies. Hamann is relatively new to inquisitorial research and inquisitorial historiography, and as a result he is cautious in how he reads, transcribes, and analyzes the documents. But despite that occasional hesitance he has provided an interesting window into the exercise of authority and resistance to that authority across a religiously and ethnically diverse mid-sixteenth-century Spanish Atlantic world.