Over the course of his distinguished career, William C. Placher has sought to stem the tide of Protestant liberalism's influence on theology. Far from being a reactionary, Placher has exposed the weaknesses in liberalism's influence by proposing the constructive system of postliberalism. Drawing on the wisdom of his teachers and mentors, Hans Frei and George Lindbeck, Placher's postliberalism ‘connect[s] a radical view of God's transcendence with a narrative Christology’ (p. ix). In previous books, Placher focused on matters such as theological method, a doctrine of God, and Christology. The publication of The Triune God: An Essay in Postliberal Theology draws together the lessons inherent in many of these works by focusing on the broader theme of God's relational nature. The strength of Placher's latest book, and his efforts as a whole, is not that he has proposed something new which removes any shroud of mystery concerning God. By contrast, its strength resides in the way he gently yet persistently reminds us that some of the greatest contributions to such a discussion were made long ago and are best understood as attempts to preserve a place for the mystery that is God.

Placher's attempt to try and reinstitute the notion of God as mystery is evident from the very beginning of The Triune God. Liberal theology offers a number of ways of proving God's existence – oftentimes in complete accommodation with various manifestations of modern thought. By contrast, Placher opens by arguing that “anything whose existence we can prove would not be God, but some sort of idol” (p. 1). The underlying assumption is that human minds are finite in terms of the scope and scale of what they can appreciate whereas God is infinite. What is at stake is the domestication of God (borrowing from a title of one of Placher's previous works –The Domestication of Transcendence, Westminster John Knox Press, 1996). In order to prove God's existence, humanity found ways to reduce God to that which we deemed knowable on our terms. By clearing away such faulty assumptions and commitments, Placher opens up space for his central argument that ‘The task of Trinitarian reflection is then to show how these three are one, and it is a task central to Christian faith’ (pp. 1–2). René Descartes, John Locke, and Immanuel Kant are among Placher's adversaries. On the surface, Thomas Aquinas's proof for God's existence may also bespeak intentions bent on domestication. By contrast, Aquinas believed that the limits of language bring us into contact with something greater than ourselves. As a result, Placher argues that ‘Like Jacob at the Jabbok, we see God only in nights of wrestling with unknown strangers and we go away limping’ (p. 41).

By reconfiguring the terms concerning debates over God's existence in chapter one of his book, Placher is now able to move forward and establish a more faithful understanding of God – an understanding that is ultimately triune in nature. Placher spends the remaining three chapters of his book creating an understanding of the narrative account of a Triune God as yielded by Scripture. Chapter two provides an understanding of the Son. Chapter three provides an understanding of the Holy Spirit. Although the fourth chapter explicitly focuses on the relational dimensions of the Trinity, discussions about the limitations of language also find their way into chapters two and three. At issue is not that Placher's language is awkward or ill‐conceived but that he is striving in some sense to focus in a singular sense on any one member of the Trinity. For example, he finds it difficult to write about the Spirit in the absence of the Father or the Son. As a result, for Placher, debates concerning topics such as the procession of the Holy Spirit are not antiquated remnants of the Church's past but vital attempts to grapple with what it means to write about God.

If the limitations of language were implicitly evident in chapters two and three, the limitations become explicitly evident in chapter four where Placher seeks to detail how the ‘These Three Are One.’ In this chapter he concludes that ‘(1) Trinitarian terminology should function less to explain the mystery than to preserve it; (2) thinking about the Trinity should move from the three to the one rather than the other way around’ (p. 121). Placher does an admirable job of working through the terminology generated by such a discussion over the course of the Church's history. The finite limitations inherent in a construct such as language can prove to be enough of a barrier. However, Placher also recognizes that the relational nature of the Trinity is difficult to describe because it stands in contrast to our fallen nature as human beings. According to Placher, ‘While I cannot be human except in relation to others, I am always curving in on myself and failing to be as fully open to such relations as I ought to be’ (p. 135). Although difficult to understand, Placher contends that ‘it is the divine three that manifest what personhood truly is’ (p. 150).

In his attempt to preserve a place for mystery, Placher surrounds himself with conversation partners spanning the Church's history. In his introduction, Placher acknowledges the significant influence that the work of Hans Urs von Balthasar has had on his own work. However, Placher may draw most frequently from the work of Karl Barth. Placher may not always agree with Barth's theological assessments. Regardless, Barth offered an indication to Hans Frei, George Lindbeck, and thus possibly to Placher as well, that efforts of contemporary theologians to grapple with the Trinity were in many ways insufficient. Drawing deeply from figures such as the Cappadocian Fathers and Augustine, Placher is able to escape the traps inherent in the theological language left by Protestant liberalism. The work of Thomas Aquinas affords him a similar way of superseding the understanding that the best work in theology reduces its object to the most infinitesimal, if not also isolated, detail.

Overall, by drawing upon the wisdom of some of the Church's most ancient and influential voices, Placher's work reconnects theology with a form of language which seeks to appreciate God's mysterious nature. A finite construct such as language betrays us at such a point, and Placher is left to work within such a system. By comparison to many of his immediate predecessors, however, Placher is keenly aware of the possibility that the greatest contribution his work can make is that it points us to a reality which cannot be fully explained. The best he can do in The Triune God is to help us focus our attention and our efforts. As a result, Placher's effort to preserve a place for the mystery that is God is, in and of itself, a significant contribution worthy of our attention. In many ways, learning to describe less about God ironically allows us to understand God as being so much more.