Luther's theology of the cross emerges early in his career and endures until its end, making it one of the most studied motifs of his theology. The mountain of scholarly attention already paid to it makes the task of Scala Christus est even more daunting: a fundamental reassessment of the historical context in which this motif emerged and a reexamination of the Heidelberg Disputation in light of that contextual analysis. Specifically, Tortoriello takes aim at the several core assumptions that have dominated academic study of Luther's theology of the cross, such as that it arose as a reaction to scholastic theology, overlapping to a degree with contemporary humanist critiques of scholasticism, and that its dominant antagonist was Erfurt nominalism, among others. These assumptions have not only influenced studies of Luther's theology of the cross but have also informed the scholarly discourse on Luther's relationship to humanism. So, while a project directed at the theology of the cross, the scope of Scala Christus est extends beyond the Heidelberg Disputation and Luther's writings alone and examines how Luther is situated within the landscape of sixteenth-century thought more broadly. It joins with those challenging humanism as a categorical framework for historical study, specifically as a movement paving the way for the Reformation (p. 12). In short, Scala Christus est is a massive undertaking.

Such a large project is aided by a clear trajectory, and Tortoriello's efforts to provide that are to be commended, though the order of the work is at times challenged by the unwieldiness of the range of material. The book is divided into two parts, the first focused on the origins of the theology of the cross, the second on the hermeneutics which accompany it. Part i opens with a decoupling of the questions at hand from the macro-categorisation of scholastic humanism to define early Luther's opposition and general theological milieu (chapter i), delivering a more nuanced and complex view of the early sixteenth-century intellectual landscape than can be provided by traditional classifications, which as Tortoriello notes, have been under scrutiny for some time (pp. 54f). This work allows the second movement, which involves situating Luther's theological development within this more complicated landscape, connecting various developments in his thoughts to new reference points within a reconstructed context. This begins with reexamining the distinction between the spirit and flesh, first in Erasmus’ writings (chapter ii) and then in Luther contra Erasmus (chapter iii), culminating in the argument that Luther's theology of the cross should be understood as much as arising in opposition to Erasmus as to Erfurt nominalism (chapter iv). From here begins the second part of the book, which examines Luther's development of the principle of Sola scriptura (chapter v), contextualising it within the distinction between the spirit and the letter (chapter vi) and Luther's opposition to Christian Kabbalah (chapter vii).

The specifics of what Tortoriello uncovers become progressively more interesting – and compelling – as the analysis of Scala Christus est develops. Disassembling the efforts of twentieth-century scholars to narrate the theological trials of the 1510s in terms of a humanistic effort to return to the theology of the early Church Fathers, Tortoriello exposes the confusing and at times contradictory nature of these debates. It is not as simple as humanism versus scholasticism, or reform-minded humanism versus scholastic humanism, and the more complicated perspective he develops permits other intellectual characters to emerge as elements to these conflicts, notably the role of Christian Kabbalah and other hermetic traditions. Likewise, the timeline of Luther's theological development and relationship with other figures is revised. Tortoriello persuasively demonstrates that an intellectual opposition to Erasmus is present as early as 1516 (p. 56) and highly influential in shaping his theology of the cross (p. 152), reversing a significant narrative in Luther studies that sees early Luther as aligned with Erasmus, or at least, more neutral toward him, until later debates over the human will (pp. 106f). Delving into Luther's earliest writings – particularly, his Dictata super Psalterium – Tortoriello shows the layers of complications behind Luther's developing thought, reevaluating old preconceptions about the relationship between Luther and nominalism as much as introducing new considerations with his reevaluation of Luther and Erasmus.

When the Heidelberg Disputation and the theology of the cross come into focus throughout the study, it is in an entirely new landscape than that many will have been accustomed to reading previously, and it will not be until this begins in the fourth chapter that readers will start to see the impact of the work that preceded. What Luther means by ‘theologian of glory’, for example, is connected more deeply to his conflict with Emser and Luther's rejection of Christian Kabbalah (p. 310), unlocking new insight into a concept pivotal to understanding the theology of the cross but rarely explained sufficiently by Luther himself. Similarly, the work of Luther's scriptural references and Pauline appeals now has a much more sufficient grounding within the context of his response to Erasmus as well as his own developing hermeneutic.

Scala Christus est is a prime example of why it is so difficult to unseat prior conceptualisations in the field of intellectual history, which is not to say that it fails. It is not merely the sway that these conceptualisations hold over prior scholarship which generates inertia; it is also that the evidence which supports them is often more present on the surface, whereas the evidence which would call them into question is more buried. For example, to show the important influence of Giovanni Pico della Mirandola, Marsilio Ficino and other fifteenth-century philosophers, he must work around the fact that none of them are referenced or directly cited in any of Erasmus’ works (p. 69), relying both on source criticism and studies of Erasmus’ social network of intellectuals to draw circumstantial but persuasive connections of their influence on his work. While not the first to explore many of these connections, the work Tortoriello puts into drawing them all together to create a background for Luther's theology of the cross is exhausting and difficult to hold together. The reader can see the appeal of constructing a monolithic scholastic humanism for Luther's theology of the cross to oppose, and while Tortoriello's work bears the burden of the exhaustion that comes with setting aside such a framework, it also evidences how essential it is to analyse the theology of the cross and similar theological developments without the aid of reductive frameworks.

In conclusion, Scala Christus est is successful in what it sets out to do, first in its aim to provide greater historical contextualisation to Luther's theology of the cross, and second in its analysis of this theology itself in light of that context. Future studies of Luther's theology in this period and of this motif in his theology will need to at least contend with Tortoriello's analysis of the various influences at work on Luther, and any who would wish to challenge his mapping of the intellectual landscape will have their work cut out for them in matching his diligence and exhaustiveness in handling such a wide range of source materials. While not a study that turns prior understandings of the theology of the cross on their ear per se, the contribution of Scala Christus est to not only our understanding of the theology of the cross but to the study of early Luther's theological development and context is significant both in what it contributes and to how it opens the way for further studies. Much like Luther's theology of the cross in relation to the Heidelberg Disputation which gave it shape, we should expect the impact of the analysis of Scala Christus est on Luther studies to extend beyond what is accomplished in this volume alone, to its author's credit.