John McGreevy has written a book of such breadth and erudition as to daunt a would-be reviewer. How to evaluate so formidable an achievement? One could, of course, devote one's allotted paragraphs exclusively to praise, all of which would be merited. (McGreevy's engaging prose would come in for prominent mention.) But what then of the critical eye that every reviewer hopes to train on even the most accomplished work of scholarship? McGreevy himself suggests a way out: “Specialists will regret what is missing,” he notes in the book's introduction, “and rightly so.” Given the remarkable range of subjects the book actually covers, however, quibbling over its inevitable omissions seems neither charitable nor fruitful. Best, perhaps, to “think out loud” about the impact of McGreevy's global perspective on my own assumptions as a historian of American Catholicism. Needless to say, his is a book from which I learned a great deal.