In an age when American Protestantism is often characterized as being divided into “ecumenical” and “evangelical” camps, Missions and Unity demonstrates that Christian mission and Christian unity have in fact been inextricably linked since the beginning of the nineteenth century. The book is divided into three sections. The first section is a historical one, providing examples of the ways in which missionaries and missionary organizations have, in the course of their work and over time, come together in movements of unity. The second and largest section of the monograph discusses ten models of Christian unity that are operative in the world today. The final and shortest section of the book recounts how Christian missions have contributed to secular movements of unity, such as the inclusion of human rights in the charter of the United Nations, and to interfaith dialogue. The work closes with a bibliography, a subject index, and a name index.

The starting point of the historical section is William Carey's suggestion made in 1806 that “a general association of all denominations of Christians, from the four quarters of the globe” be held every ten years in South Africa (3). A brief review of missionary movements that worked for unity before Carey reminds us that Carey did not sound the first call for ecumenical efforts in mission, but his importance is nevertheless asserted. In succeeding chapters, the author describes various formal and informal cooperative ventures by Protestant missionaries from 1792 to the present. Unusually for a historical section, the more recent developments are described more briefly than the earlier ones.

In the second part of the volume the author discerns ten different models of Christian unity. These are, respectively, “Unity Through A Global Church,” with the Roman Catholic Church as the prime example; “World Conciliarism,” typified by the World Council of Churches; “Christian World Communions,” such as the Lutheran World Federation; “World Associations,” like the Lausanne Committee for World Evangelization; “Regional and National Voluntarism,” exemplified by the United Mission to Nepal; “Regional and National Councils,” which are found all over the world (Christian Conference of Asia, All Africa Conference of Churches to name but two); “Towards Church Union,” as happened in the Church of South India; and three models of “Local Unity”: local united churches (such as union churches), local councils (that is, local councils of churches), and local associations (like BCCs and Taize). A convenient chart showing the conceptual connections between these models is provided in the Introduction (xxiii).

Part 3 of the book is entitled “Wider Ecumenism.” In this section, Thomas discusses non-ecclesial aspects of the movements of Christian mission and unity. One chapter deals with Christian efforts in the promotion of human rights, peace, and justice, especially those efforts leading up to the establishment of the United Nations. The penultimate chapter briefly narrates the history of mission organizations in dealing with the often contentious issue of interfaith dialogue. The book closes with a summary conclusion.

This work is a great boon to those who do not know the joint history of mission and ecumenism. As suggested in the opening of this review, it is quite ironic that American Protestants often think of themselves as “ecumenical liberals” or “conservative evangelicals,” when it is the missionary movement to spread the gospel of Jesus Christ that gave birth to and nurtured modern ecumenism. Furthermore, the ten models of unity outlined by the author helpfully point to the great diversity of Christian efforts to join together into one body, either institutionally or in ministry or both. The author, then, urges Protestant readers to think more deeply about convictions they might hold quite unreflectively about their own religious identity.

While the strengths of this book are many, it does have some drawbacks. The first is that it really does not present any new material to those who are familiar with the history and workings of Protestant ecumenism. While the ten models arrange ecumenical movements in a novel and helpful way, it is not clear what benefits arise from this particular categorization. Secondly, the book suffers from the lack of any argument or thesis. It is true that the author makes clear that he “chose a descriptive and analytical approach—not a normative one” (xxii). Moreover, the book is not meant to be a history of the ecumenical movement (xxiii). However, the work comes across too much as a string of events wherein mission and unity coincided. Without an argument, the reader is not able to grapple with some of the most basic questions regarding missions and unity, such as why evangelism and ecumenism have become separated from each other, or why numerous movements for unity have collapsed, or why there are so many different models of unity.

Even with these problems, the book will be very useful to Protestants who do not know much if anything about the workings of ecumenism, past and present. It can be used profitably by church study groups and in introductory seminary courses on mission, evangelism, and ecumenism.