This is an extraordinary book that distills a heady, potentially unwieldy topic into a relatively compact volume. Mark McIntosh draws on his expertise in systematic theology, historical theology and Christian mysticism to make a complex argument. Although he worries that this is not the lengthy study he had originally planned, where, evidently, he would have gone into more depth, his erudition blended with evident traces of praxis are more than sufficient to draw us into this world of ideas and convince us of its continued relevance.

McIntosh summarises what he means by the ‘divine ideas tradition’ as follows: its adherents held that ‘in God's eternal knowing and loving of Godself, that is, in the eternal begetting of the Word and breathing forth of the Spirit, God also knows and loves all the ways in which creatures might participate in God's life through God's gift to each creature of existence’ (p. 12). While the divine ideas tradition overlaps considerably with the broader Christian Platonic tradition, it extends further and includes authors not easily categorised as Platonic. According to McIntosh, ‘the divine ideas are far more present implicitly throughout the whole range of Christian teaching than any particular explicit references to them might suggest’ (p. 7). Even when they are recognised, however, ‘there is a tendency among the best scholars of the ideas to consider them, even in their most robust Neoplatonic versions, as a hypothesis to account for some difficulties – always puzzling, problematic in origin, contested in validity, and in any case deeply enmeshed in the professional disciplinary thickets of philosophical metaphysics and epistemology’ (p. 17). McIntosh corrects that reflex by unveiling the trinitarian dimensions of the divine ideas tradition, linking it necessarily to contemplative practices, and underscoring the necessary relation between love and knowledge.

McIntosh's first task is the clarification of ideas, distinguishing modern preconceptions from this more ancient mindset. Whereas ‘for thinkers in modernity, we arrive at certainty through arguments we make and the undefeated status of one set of our ideas over that of others’, for those belonging to the divine ideas tradition, ‘the object of our thought brings our minds to life, actualizing our minds according to the idea (intelligible form) which “in-forms” them when the idea arouses them to thought’ (p. 19). The divine ideas tradition is thus deeply incarnational: ‘ideas (in this older tradition) not only have a primary agency out in the world (as opposed to only within our minds), but that they also need not be pitted over against matter and bodiliness’ (p. 20).

The book comprises an introduction and five chapters organised in a familiar pattern of exitus and reditus: the Trinity; Creator and creation; incarnation and resurrection; and eschatology. Chapter 1 is itself a kind of introduction, explaining ‘the divine ideas in the mystery of the Trinity’ (p. 12), yet also anticipating the arguments of the following chapters. Chapter 2, ‘The Intelligible Beauty of Creation’, retrieves a compelling theology of nature that should be of great interest to scholars interested in eco-theology and environmental ethics. McIntosh there argues:

Chapters 3 and 4, ‘The Saving Word of All Things: The Incarnate Word as Bearer of Creation's Truth’ and ‘The Resurrection of Christ and the True Life of All Creatures’, respectively, explore a rich christology from above that, McIntosh contends, ‘would require us to be open in some sense to a new social imaginary, a mindset or way of looking at reality that is receptive to an unexpected depth of meaning, to sensing reality as a kind of communication’ (p. 124). Finally, chapter 5, ‘Beatitude and the Goodness of Truth’, focuses on what McIntosh calls four inter-participatory ‘events of truth’: ‘God's everlasting knowing and loving of Godself’, ‘human participation in intelligibility’, ‘the expression in our world of God's eternal knowing and loving of Godself’ and ‘human sharing in God's beatitude’ (p. 166).

Although McIntosh devotes most of his time to examination of medieval authors (e.g. Augustine, Pseudo-Dionysius, John Scotus Eriugena, Anselm of Canterbury, Thomas Aquinas, Bonaventure, Hadewijch of Antwerp, Meister Eckhart, Catherine of Siena and Marsilio Ficino), with the exception of a few excursions into the modern (e.g. C. S. Lewis and Charles Taylor), in fact he has more to offer our contemporary reflections than an education about ancient views. His is a call for a ‘New Social Imaginary’ (p. 124) not unlike that developed by Pope Francis in his encyclical on the environment, Laudato Si’. In The Divine Ideas Tradition, we have a new instance of ressourcement and aggiornamento in a new time of crisis: a return to deep sources in order to understand and meet our time in the hopes of preserving a future. Indeed, McIntosh undertook this book ‘increasingly concerned that the human community's response to global climate change was sadly vitiated by denials of truth’ (p. vii). His aim, in part, was to reclaim ‘a theological perspective that honors truth with profound reverence’ (p. vii).

This is not an introductory volume. For those scholars acquainted with the thinkers treated here, McIntosh provides deep background that is illuminating and fascinating. Specialists will learn much. For others, there is still much to be gleaned. The book radiates a sense that the reader is in the good hands of an author who himself intimately knows this contemplative tradition. His years of research into the topic became more personal in writing this volume, McIntosh tells us, when he was diagnosed with ALS (p. viii). That makes this accomplishment all the more amazing, since he could no longer access his notes and glosses. Yet the book is better for its relative succinctness. McIntosh's erudition is impressive and his contribution to theology and philosophy significant.