I have been eagerly awaiting the publication of Heathen: Religion and Race in American History ever since I first heard that Kathryn Gin Lum was working on a long history of “heathens” in US history. I had, at the time, just finished my first book, Christian Imperialism: Converting the World in the Early American Republic (Cornell, 2015), and I had been doing a lot of thinking about “heathens” in nineteenth-century American culture. Specifically, I had trying to understand how white Protestant missionaries understood the concepts of heathenism, civilization, and conversion, and how these ideas shaped their decision-making about where they should focus their evangelistic attention. In Christian Imperialism, I argued that missionaries understood “the heathen world” to be a big place, but they did not understand all heathens to be equally heathenish. Some were more civilized than others, and thus made better candidates for conversion – and, as I found, those who were more “civilized” tended to be in or on the margins of Anglo-American empire. I called the rubric that missionaries used to judge the relative heathenism of different populations the “hierarchy of heathenism.” But I still had a lot of questions, and I hoped that Lum's work would answer them. I have not been disappointed.