Gavin Ortlund's book is not a commentary in the strictest scholarly sense, i.e. a line-by-line analysis of the text. However, it does engage with the text in a clear and often insightful manner. The work is divided into five chapters plus an introduction and conclusion. Prior to the discussion of the text, the first two chapters are concerned with ‘method’ and ‘reception’. In chapter i, ‘The method of the Proslogion: getting beyond “The problem of Anselm”’, Ortlund discusses the question of Anselm's perceived rationalism and the relation between faith and reason in Anselm. In chapter ii, ‘The interpretation of the Proslogion: historical reception and contemporary trends’, he is keen to point us to some recent French and German scholarship that he believes has been under-appreciated amongst English-speaking scholars, singling out the work of Paul Gilbert, Yves Cattin, Georgi Kapriev and Siegfried Karl for further discussion. That said, he does not do this at the expense of engaging with a wider body of Anselmian literature. The text proper is discussed in the chapters that follow: chapter iii, ‘The purpose of the Proslogion: excitatio and argumentum in chapters 1-4’; chapter iv, ‘The structure of the Proslogion: spirals upward from chapter 5 to chapter 22’; and Chapter v, ‘The climax of the Proslogion: the Visio dei in chapters 23–26’.

Rather than analysing the logical structure of the Proslogion, and assessing its argument(s) for its (their) logical validity and soundness, Ortlund's approach is more ‘theological’ and ‘literary’. He is keen to stress the error involved in focusing on Proslogion 2–4 at the expense of the remainder of the text. As he rightly points out in the introduction and chapter iii (pp. 7, 81), Anselm states his purpose as wanting ‘to prove that God truly is, that he is the highest good [summum bonum] needing no other and that which all things need for their being and well-being, and whatever else we believe about the divine substance’. Clearly that is not achieved in Proslogion 2–4.

Ortlund's approach has its advantages and disadvantages. We are not subjected to the lengthy formalistic (and occasionally procrustean) reconstructions of analytical philosophers. But in the end we are no nearer knowing whether Anselm's argument really works in a sense that cannot be captured by an account of a ‘pursuit of joy’ or ‘ascent to God’. (Ortlund appears to think the argument sound, but does not tell us why [p. 9].) Anselm makes it clear from the beginning that the success of his project in the Proslogion is bound up with its argumentative power. Not that he considers it a necessary condition for faith that it is rationally justified, but he thinks it can be and in this case is, which is why he wrote the Proslogion (and the Monologion and Cur deus homo).

Ortlund plumps for what I would call ‘weaker’ or ‘looser’ interpretations of the terms probare and argumentum. He suggests that ‘in Anselm's context the verb to prove does not strictly signify a process of rational justification, as in a syllogism, which moves from premises to conclusion – it is commonly used in a less technical way to simply mean to examine or judge’ (p. 81). I find this unconvincing, since Anselm is a technical dialectician, as we can see from De grammatico, where he instructs his student to construct and reconstruct syllogisms as part of a process of more intense consideration and understanding. De grammatico is a good place to look if we want to understand what Anselm means by probare/probatio, since he employs these terms twenty-six times in that work, and from the outset in a manner discounted by Ortlund. Moreover, there is good reason to suppose that the unum argumentum is a syllogism. Of course, the precise meaning of the term argumentum can be difficult to pin down in a particular context. For example, it could be taken to mean a term, a proposition, an argument or the form of an argument (argumentation). In his In Ciceronis topica, Boethius suggests different ways in which we can understand the terms argument and argumentation, but always with reference to the syllogism/ratiocination. Whatever the relation between faith and reason in Anselm's thought, something Ortlund discusses with some sensitivity, it is simply the case that Anselm employs arguments which are grounded in Boethian dialectic and syllogistic (and not just Boethian – see, for example, the not yet fully appreciated influence of the rhetorical forms of argument discussed by Cicero and Quintilian).

Ortlund is surely correct in arguing that the aim of the Proslogion is ‘not only to direct the mind to God as the summum of all reality, but to direct the soul to God as the bonum of all happiness’ (p. 221). He finishes with a conclusion which summarises succinctly his main thesis: ‘the ultimate concern animating the [Proslogion] is not God's existence as such, or even God's nature, but specifically God's existence and nature as the fulfillment of all human longing’ (pp. 229f.). This reflects the point that he made at the beginning of his ‘commentary’ (p. 7), that the proof concerns ‘the highest good [summum bonum] needing no other and that which all things need for their being and well-being’. In other words, the Proslogion concerns not just God, but creation's dependence on God as the summum bonum, which is expressed by Anselm in the final prayer of the final chapter in terms of a journey towards the fullness of joy. (Thus, it may be no coincidence that the anonymous author of the contemporaneous attempt to refute the argument of the Proslogion (the Pro insipiente) was given the soubriquet ‘Gaunilo’ = Gaudium in nihilo?) With his greater focus on the final chapters and a broader reading of the text, Ortlund has provided a valuable service in helping to rebalance the hermeneutics of the Proslogion.