Why Niebuhr now? That question is the title of John Patrick Diggins’s last book. Diggins was asking the question about the life and writing of Reinhold Niebuhr. His book—published posthumously—probed Niebuhr’s work in relation to the challenges facing American society in the early 21st century. Jon Diefenthaler is asking the same question about the life and work of H. Richard Niebuhr. Diefenthaler wants H. Richard Niebuhr to offer us his own answers to the question, and has compiled a breathtaking set of Niebuhr’s texts in order to show Niebuhr’s lasting relevance. The answers to the question “Why H. Richard Niebuhr now?” do not come only from Niebuhr’s pen, though; they come from Diefenthaler’s as well. As the title of this book suggests, Diefenthaler is concerned primarily with Niebuhr’s descriptive and prescriptive discussions of how the church relates to non-Christian society. The collection of texts that Diefenthaler has produced is impressive and allows H. Richard Niebuhr’s voice to come through clearly and effectively on the topic of the church’s relationship with the world. Graduate students and scholars interested in H. Richard Niebuhr will find this collection to be a very valuable resource. In addition, Diefenthaler’s case for Niebuhr’s enduring relevance is commendable and justified in light of Niebuhr’s corpus, even if (in my opinion) the invocation of Niebuhr does not go far enough in responding to contemporary social and political challenges.
 First: the collection of primary texts is impressive in terms of range, content, and organization. This book provides a truly stunning collection of H. Richard Niebuhr’s primary texts. The texts span from 1917 to 1959. Diefenthaler has two major goals in presenting this collection: context and variety (xxiv). In order to meet the goal of showing how Niebuhr responded to his historical context, Diefenthaler organizes the book into three parts corresponding to major periods in Niebuhr’s life: “formative years in the Evangelical Synod (1914-1929), the decade of the great Depression (1930-1940), and World War II and its aftermath (1941-1962)” (xxiv). The texts he chooses capably demonstrate Niebuhr’s attention to social, economic, and political crises. As for the other goal, these texts exhibit the remarkable variety of writing that Niebuhr produced. Readers will find a powerful reminder of the wide range of Niebuhr’s interests and abilities. He was a theologian, an ethicist, an intellectual historian, a sociologist, a political commentator, a teacher, a poet, and more. These genres are well represented in this collection. Diefenthaler set for himself the goals of showing H. Richard Niebuhr’s responsiveness to his historical contexts and authorial range, and in my opinion, he met those goals very well.
 In terms of presentation, the book is divided into three parts, and each part is comprised of three or four chapters–there are ten total chapters in the book. Each chapter contains several of Niebuhr’s primary texts. Diefenthaler offers a short introduction to each chapter of the book. These introductions span about five pages each and orient the reader to the general historical context that the following chapter engages. He also offers paragraph-long introductions to each primary text within every chapter. These introductions are quite helpful in terms of providing context and reminding readers of historical events, Niebuhr’s intellectual maturation, and so forth. The sheer quantity of primary texts justifies the divisions of this book into parts and chapters, but this many divisions, introductions, and subheadings may confuse a casual reader.
 In terms of the primary theme of the texts, Diefenthaler chooses these texts because they demonstrate Niebuhr’s attention to the paradoxical relationship between church and world. In his introduction, Diefenthaler explains Niebuhr’s analysis of this relationship, emphasizing Niebuhr’s intellectual development and the publication of three major texts: The Social Sources of Denominationalism, The Kingdom of God in America, and Christ and Culture. The motif that emerges in this introduction—and that resurfaces throughout the primary texts—is paradox. The church must “be in but not of the world” (xii). At a minimum, this means that the church must retain its distinctiveness but not withdraw from the world. It must serve the world without being shaped too decisively by it. The church must understand that it is inevitably formed by non-Christian forces, yet at the same time maintain the priority of its gospel calling. The church must believe it has something unique and important to show the world, while also recognizing its own inclination to misunderstand its calling. Paradox means all of this and more, as Diefenthaler and Niebuhr present the idea. In his introduction, Diefenthaler also summarizes several critiques of Niebuhr’s discussion of the relationship of church and world. He categorizes Stanley Hauerwas, William Willimon, John Howard Yoder, and Glen Stassen as “critics.” Martin Marty and James Gustafson are “defenders.” George Marsden and D.A. Carson are “fixers” (xv-xxi). Diefenthaler is unsatisfied with the critics and the fixers, and offers this book in large part as a way to allow Niebuhr to defend his conception of the paradoxical interplay between church and world. Thus, each chapter and each text speak to the theme of “church/world relations” to varying degrees. One of the pleasures of reading this book is thinking about each text in light of the motif of “paradox of church and world.” On first reading, it was not always immediately obvious how certain texts related to the theme. But Diefenthaler’s introduction illuminates ways of reading such texts that would not have occurred to me if I had encountered them on my own. I wonder about other themes that might hold these texts together, as well. Students of Niebuhr will recognize familiar ideas such as responsibility and monotheism as consistent refrains throughout these texts.
 Second: Diefenthaler’s argument about Niebuhr’s relevance in the early 21st century is commendable. In the epilogue, he tells a familiar story about the decline of Christianity’s influence in American society during the 20th and 21st centuries. This story includes the contentions that Americans are going to church less, Christianity has generally become less meaningful and influential, and religious pluralism is on the rise. I think that story tends to be overstated in many ways. For example, it may be true that fewer numbers of Americans self-identify as Christians, but as an overall percentage of the American population, Christianity is still dominant. The Pew study that revealed a recent rise of the “nones” also reports that as of 2014, 70.6% of Americans are still Christian. Similarly, pluralism was present in the American colonies long before the United States was a nation. This pluralism was not simply a matter of the standard Judeo-Christian heritage we tend to assume: many African slaves were Muslim and/or practiced traditional West African religions, for example. I find it problematic that Diefenthaler rehearses this common story about the decline of Christianity’s influence in the late 20th and early 21st centuries without acknowledging the complexity of many claims on which the story is based. In addition, Diefenthaler does not include any footnotes as he tells the story of Christianity’s decline in America (500-502). The primary purpose of the book is to offer selected works of H. Richard Niebuhr organized around the theme of paradox, so offering a detailed academic account of this narrative may not be Diefenthaler’s priority. Even still, if we are to determine H. Richard Niebuhr’s relevance, and that relevance depends on a commonly-told story about Christianity’s decline, we should aim for as much accuracy and precision in telling the story as possible.
 Assuming the general merits of the story, though, Diefenthaler’s suggestions about Niebuhr’s relevance are promising. Specifically, he makes four suggestions. Niebuhr can help us: 1) break down the division that churches uncritically imagine between sacred and profane; 2) expose the false gods (such as capitalism, nationalism, etc.) that we worship today; 3) identify Christian hypocrisy and arrogance and encourage repentance in their place, and; 4) adopt a more hospitable response to pluralism. These points are all rooted firmly in Niebuhr’s work, and they are all urgent needs in today’s social and political climate. Our political society desperately needs more Christians who cultivate the virtue of hospitality toward their neighbors of different religion, race, gender, and so forth. Having read Diefenthaler’s collection of Niebuhr’s work, I am convinced that Niebuhr can help Christians grow in this regard. And yet, laudable though this project is, I fear that it is not strong enough as a response to the forms of religious, racial, and gendered oppression that mark our political society. As presidential candidates, legislators, and media representatives openly marginalize people on the basis of religion, race, and gender, we need Christians who go beyond merely being open to difference. We need Christians who work to actively restrain America’s forces of sin and also empower those who are neglected and demonized in our political society. When entire groups such as “Mexicans” are branded “rapists and murders” and Muslim refugees are labeled as terrorists, openness cannot be sufficient. Nor can breaking down boundaries between sacred and profane, resisting false gods, or exposing Christian arrogance be sufficient. Restraint and empowerment must become active goals. Can H. Richard Niebuhr motivate us toward such movements of restraint and empowerment? I think so. Diefenthaler’s collection includes these lines, which Niebuhr wrote while watching the ascent of National Socialism in Germany in 1930:
At this point…there seems to be a dubious hiatus between the public expressions of the leaders and the actual program of the party. This promises the exclusion of all Jews from public office, their disenfranchisement and sometimes seems to threatened deportation. The converse of this measureless hate of the Jews is the old chauvinism, the old proud self-exaltation of isolated nationalism and its associate—militarism. (190)
Why Niebuhr now? This quotation and the 2016 US presidential primary campaigns answer that question clearly. Diefenthaler’s collection and the contemporary US political climate have persuaded me that H. Richard Niebuhr’s work is still relevant. But I hope that a revival of interest in Niebuhr leads to more than mere openness, toward active restraint of sin and robust empowerment of the American least of these.