In the effort to assess a range of Christian responses to religious diversity, lead author Tilley compares this volume to two antecedents: Alan Race’s Christians and Religious Pluralism (1983) and Paul Knitter’s Introducing Theologies of Religions (2002). In place of the former’s three categories (exclusivism, inclusivism, pluralism) and the latter’s four (replacement, fulfillment, mutuality, acceptance), Tilley and his collaborators—all members of a 2006 graduate seminar at the University of Dayton—identify the main positions as “classic and contemporary inclusivisms” of Karl Rahner, Jacques Dupuis and Gavin D’Costa (chs. 4-5), John Hick’s incipient and Knitter’s fully developed “mutualism” (ch. 6), the different forms of “particularism” represented by Paul Griffiths, Joseph DiNoia, and Mark Heim (chs. 7-8), and, finally, the “comparative theology” of Francis Clooney, James Fredericks and various practitioners and theorists of multiple religious belonging (chs. 9-10).

This volume moves beyond previous typologies in its candid recognition of the genuine “incommensurability” between and among those surveyed (xiv). In particular, whereas Race and Knitter’s arrangements suggest a continuous movement from lesser to greater levels of interreligious engagement, the present volume places its strongest emphasis on a fundamental divide between the “foundationalist” positions of inclusivists and some mutualists, on the one side, and the “nonfoundationalist” approaches of Knitter among the mutualists and of most particularists and comparative theologians, on the other. The former “assume that theory grounds practice/praxis,” whereas the latter “find that theory is an outgrowth of practice/praxis” (xv). Since these broad groups differ in their most basic assumptions, Tilley argues, representing them as various “types” of the same genus ultimately confuses more than it clarifies.

Such incommensurability does not release volume authors from the obligation to offer critical evaluation. Quite to the contrary. Borrowing from the earlier work of Robert Schreiter and Tilley himself, however, they contend that the criteria for such evaluation will always be “sited” in a local context and oriented toward the concrete practice of the faith in that local context. Thus, chapter 2 draws from the work of Robert Wuthnow and other social theorists to offer “five key characteristics most important for constructing a theology of religious diversity” in the U.S. context, including immigration, intrinsic diversity, political nonestablishment of religion, consumerism and globalization (14). Chapter 3, in turn, develops four practical “shalt nots” that must guide any broadly Catholic or “mainstream Christian” approach to the issue. Christians are thus prohibited from denying any of: 1. “God’s universal salvific will” (50), 2. “the sufficiency of God’s salvation in and through Jesus Christ” (54), 3. “the necessity of the church for salvation” (57), or 4. “the dignity of each and all human persons” (60). Application of these principles exclude some positions at the front end, including those conventionally treated under the rubric of “exclusivism,” as well as shaping the final evaluative section of each chapter. Dupuis’ inclusivism, Knitter’s mutualism and comparative theology receive the most favourable individual assessments according to these four principles. Sustained evaluation in light of the five characteristics of the U.S. context is, on the other hand, largely deferred to the eleventh and final chapter.

The resolutely local and practical orientation of the volume, as well as its effective and accessible survey, commend it for a broad readership. This distinctive focus is also, at the same time, what prevents the work from being reckoned a complete success. First of all, the question of choosing representative positions becomes more difficult when one holds oneself accountable, not merely to an adequate typology, but also to a complex social reality. This reader wonders, for example, why homespun U.S. collaborations like the Comparative Religious Ideas Seminar or trans-Atlantic projects like the Scriptural Reasoning network seem to find no place in its pages, or how the contributions of John Cobb and especially Diana Eck to the American public sphere could be limited to passing remarks. In addition, the authors’ “no necessary theory” conclusion, which suggests that none of the surveyed approaches can be either completely dismissed or definitively upheld except in their provisional relations to a similarly diverse cluster of dialogical practices (189-91), borders on tautology. In this respect, Alan Race and Paul Knitter’s earlier treatments offered greater coherence, with the former pressing the question of historical knowledge at every turn and the latter drawing balanced insights from every corner.

But perhaps this is part of the genius of the present volume. Neither the facts of religious diversity nor the specific texture of the American situation lend themselves to straightforward, coherent assessments. So Tilley and his students offer a more authentic response: a complex, even messy conversation, beginning in their 2006 seminar, culminating in this 2007 book, and intended to continue in other U.S. classrooms. Were I teaching in the U.S., I would seriously consider using this text to facilitate precisely such messy conversations.