Here is a book that, by rights, should transform the way that Aquinas is taught among undergraduates and seminarians. Frederick Bauerschmidt of Loyola College has introduced the Summa Theologiae, thoughtfully produced extracts of it, and then expanded on it with rich explanations and examples in footnotes. One of the greatest assets of the book is the way that Bauerschmidt is forthcoming about how he wants students to read. In this, an implicit argument is made throughout. Holy Teaching differs from many other anthologies of the Angelic Doctor's great Summa by paying scrupulous attention to questions of theology rather than philosophy. For example, it shows that Aquinas was not just concerned with Aristotle for its own sake, but was so in order to expound on topics like christology and the sacraments. Bauerschmidt dispenses with the traditional (though false) idea that Aquinas merely baptised philosophy; instead, philosophy is enlisted to help explain the revelation of God, supremely in Christ.

In this way, the book represents a significant contribution which owes a debt to and furthers a recent trend which emphasises the thoroughgoing theological nature of Aquinas' thought. And while the so-called ‘new Aquinas’ thinkers (we should really say the old Aquinas) have a lot to say about, for instance, the christological shape of all reality, including those aspects which might wrongly be supposed to be ‘natural’ in a somehow non-theological sense, this volume goes further. It attempts to help form readers in the spirit of the Summa itself, perhaps recalling the two senses of communicare as Aquinas described them: both the passing on of information and crucially also sharing which cannot help but transform the reader. For Aquinas, the incarnation supremely enacts this, since Christ is the goodness of God which shares itself (p. 165). The Summa is more than an impressive encyclopedia of information since it follows precisely this kind of incarnational logic. It cannot be received without causing a change. For readers, this means that sacra doctrina is bound up with the virtues required to know it, which is another way of saying that knowing Christ is the purpose of the Summa.

As Bauerschmidt explains, the tradition of excerpting the ostensibly most important part of the Summa as stand-alone arguments cannot help but distort the theological nature of those arguments. Too often, the famous Five Ways are thought to be attempts at sufficient proofs for God's existence when, in fact, the intent was actually much more modest than this. They show that questions about the existence of things are not irrational, nor are they unanswerable. But they do not set out to prove the Christian God (which is not to gainsay how some may still find them convincing in this respect). Only a scheme which sharply separates reason from faith would lead us to think that Aquinas must have failed in what is perceived to be his intention. One hopes that Bauerschmidt's concise explanations will accompany the quick and dirty dismissal these arguments are made to endure in countless classrooms.

Bauerschmidt makes clear how, for Aquinas, reason is both partially enlisted and partially by-passed by theology. While reason cannot prove what God has revealed in scripture, not least as it regards historical, and therefore contingent, matters, it can explain the fittingness (conveniens) of why God has acted in one way rather than another. ‘Fittingness’ denotes a kind of necessity, not out of logical or other compulsion, since it is impossible to speak this way about God for whom act and essence are one. Nevertheless, theologians can describe a posteriori how God's acts are beautiful.

Let us take a subtle example from the text itself. Bauerschmidt notices and explains this theme in the question of whether or not Christ should have committed his teaching to writing. The typical practice in the Summa is to invoke a traditional authority such as scripture or one of the Fathers. In this case, however, Aquinas is content to respond simply that there are no books written by Christ in the canon (p. 220). Bauerschmidt rightly notes that the authority cited is implicit, that it is the authority of the church itself since it was responsible for gathering the canon. And while the logic is slightly circular, it honestly displays how the church's faith rests in part on those things it has produced by way of its own history, which is of course to say that Christian history is imbued with the actions of God and therefore carries a concomitant authority.

Furthermore, Bauerschmidt reflects for the reader's benefit on how Aquinas' response does not make a case for answering whether Christ should have written anything: the fact that nothing he may have written has appeared in scripture only means that, had he written something, it must not be worth reading. But this does provide a framework for thinking within – which Bauerschmidt does – especially about how Christ himself is the Word of God and even scripture as a witness to that Word is secondary (p. 221). Taken together, these points remind us that the nature of the church's witness is one with that of scripture.

Readers will not be surprised that Bauerschmidt aims to correct an imbalance in how the Summa has been read by focusing heavily on the oft-neglected Third Part. It is here that questions of the incarnation, Mary, the suffering of Christ and the sacraments are addressed. Bauerschmidt thinks the other sections should be seen as leading up to this one. We again encounter here the emphasis on the sacramental nature of the reader's activity. By reading, readers participate in the formation the text partially enacts since a sacrament is simultaneously both a sign and a cause. This cannot be true of all reading, of course; but Aquinas knew that writing on sacra doctrina is unlike writing on anything else. Bauerschmidt is to be applauded for succeeding remarkably well in maintaining the mystery of this holy teaching. I can therefore think of no better way of introducing students to the Summa of Aquinas than through this book. Only a writer who is so obviously at ease with medieval theology and who so evidently shares the mind and heart of Aquinas could have written it.