In every field of thought and scholarship there come moments when it is time to summarize the present state of research and reflection and thereby to provide a starting point for the next stage. In the natural sciences and some of the mathematically oriented social sciences, where the usual medium of publication is the scientific paper, disseminated as quickly as possible, these moments represent the opportunity to put out a book; but in the humanities, where the full-length scholarly article and the monograph are still dominant, they are an opportunity to put together a reference work: a manual, a collection of scholarly essays, a dictionary, or even an entire encyclopedia.

Quite apart from the symbolic or real import of the year 2000, this is such a moment for the serious study of Christianity as a historical and a contemporary phenomenon, and the Encyclopedia of Christianity is the outcome of a serious scholarly effort to supply both a summary and a starting point. For in one branch of theology after another, the investigations and the debates of the generations since the Second World War now permit, indeed demand, a job of scholarly cartography, not to arrest the continuing development of the discipline but to facilitate it. And the articles in this encyclopedia have been able to take good advantage of that situation, by putting old and seemingly irrelevant questions into a new light and by examining new questions—and new answers—that have come out of the changed situation of Christian faith and obedience at the end of the second millennium. Although eventually I had to withdraw from the editorial board of the German Evangelisches Kirchenlexikon, on which the EC is based, because of the assignment of delivering the Gifford Lectures, followed by my election as president of the American Academy of Arts and Sciences, I was able to join with my colleagues of that board in the planning and design of the set. We reviewed one comprehensive list of article titles after another—typically, the German word for such a list was Stichwörterverzeichnis—asking whether that was still the category to which a reader of the twentieth (or twenty-first!) century would naturally turn for information and guidance.

One of the most striking such changes is the truly global character of the Christian faith at the conclusion of the twentieth century. Ever since the command to carry the gospel “into all the world” and to “make disciples of all nations,” Christianity has aspired to be universal: one of the earliest marks of the church, an attribute that found its way into many of the major creeds, was “catholic,” meaning universal. The early legends about the twelve apostles described them as traveling to all the corners of the then-known world. But it was only the then-known world. With the modern voyages of discovery, ancient peoples, ancient civilizations, and ancient religions became part of the European and the Christian consciousness, as well as the objects of Christian missions, above all in what the late historian of the expansion of Christianity and my Yale colleague Kenneth Scott Latourette called “the great century” of missions, the nineteenth. Yet it was not until the century which followed that the full implications of this development became clear. In one article after another of the EC, the reader will be caught up short by the reminder of a Christian belief or practice or organizational form that reflects an Asian or African or Latin-American cultural context and that both enriches and challenges conventional Western understandings of what it means to be Christian. Indeed, the very titles of many of the articles themselves present such a challenge, as even a cursory review of the entries will show.

But what has happened to the Christian movement during the twentieth century is not only globalization; “the great new fact of Christian history” has been the cluster of experiences, insights, and shocks associated with the term “ecumenical.” As applied, for example, to the first seven “ecumenical” councils of the church, that term used to refer to the Mediterranean world, to the Christian imperium Romanum governed by a Christian emperor, and to the five historic patriarchates inherited from the early church. The twentieth-century process of redefining the word “ecumenical” has left its mark on ¶every Christian group, and no traditional conviction or problem has remained unaffected. From a concern of various Protestant churches to reexamine their historic divisions and differences in the light of Scripture and in the light of their rediscovery of one another, the ecumenical movement has gone on to engage the participation, with varying mixtures of caution and enthusiasm, of Roman Catholic and Eastern Orthodox partners in the conversation; and that too has left its imprint on these pages. It is a useful, if rather sobering, exercise to flip at random through the EC, reading first an article with a geographic designation, then one with a theological title, but seeing in each of them a “strange new world.”

Nor should the reader of these volumes forget that its editors and contributors, like their predecessors in every century of Christian history, are conscious participants in the culture and outlook of their own time. I suspect that, for many readers, one of the unexpected differences between the great German and French theological encyclopedias of the past, on which we have all depended, and the EC is its reliance on the methodology of the various social sciences: Max Weber and Ernst Troeltsch are present in these articles, even when their names do not appear in the bibliography. Also among those present are the considerably less sympathetic modern interpreters of Christianity, Karl Marx and Sigmund Freud. As a result of this serious but critical involvement of the EC in the spirit and methodology of our time, it will certainly be far more accessible and useful than earlier works were to those readers who do not regard themselves as members of any Christian group or church but who want to know and understand Christian beliefs and teachings. It should therefore also commend itself to public libraries and to school libraries at every educational level from elementary school to university.

Being something of a reference book freak, I have since my student days been surrounding myself in my study with general and specialized encyclopedias, foreign language lexica, and dictionaries of many other kinds, which (at least so far) no electronic resources have successfully replaced. Whether I am engaged in my own scholarly research in the primary sources or simply reading within or beyond my own discipline, I feel insecure without the ever present help of “hunt-and-find” works that will give me, more or less instantaneously, a bibliographic reference, a statistic, a date, a name, or a definition. Reference works such as the EC quickly become indispensable for that “hunt-and-find” purpose (if only when working on the Sunday crossword puzzle). But it is gross neglect of a major intellectual resource, and of a great personal pleasure, to leave it at that. Over and over, I turn to my reference works in order to get a conspectus that will enable me to review, with a mixture of reminder and new insight, some area of human endeavor or speculation. I have been doing just that with the German version as the individual volumes have appeared, and now I shall be able to do it even more easily and even more profitably with the English EC. It is a great indoor sport, and I heartily recommend it.