This book develops and argues as its principal thesis that ‘the tendency to harmonize the philosophies of Plato and Aristotle … reigned, with ups and downs, throughout the history of Neoplatonism form [sic] Porphyry to Simplicius, without any known exception’ (p. 17). The narrative is divided into two main parts. In the first part, H. outlines his supporting documentation and lines of argument for this thesis. In so doing, he pays some special attention to the distinction between the Athenian and the Alexandrian Neoplatonist schools, arguing against ‘the hypothesis [that] has been constructed that there exists a profound difference between the Alexandrian and Athenian school’ (p. 13); rather, H. argues, the two schools were ‘linked … by permanent teacher-student relations’ (p. 25) so that ‘[i]f one leaves aside the constraint exerted by Christians on pagans … a constraint that was much stronger at Alexandria than at Athens – the only difference between the teaching of Neoplatonic philosophy at Athens and the teaching delivered at Alexandria consists, in my opinion, in its organization’ (pp. 22–3).

H. appeals to a passage from Hierocles to illustrate his understanding of this ‘harmonizing’ tendency, wherein Hierocles ‘affirms “the agreement between the thought of Plato and that of Aristotle”… not on every point, but “in the most important and necessary doctrines”’(p. 41). Indeed, H. argues, ‘I could not name any Neoplatonist who defended a one hundred percent agreement between the philosophies of Plato and Aristotle’ (pp. 41–2). H. here also considers the genesis of the Neoplatonists’ harmonising tendency and concludes that ‘[a]mong the Neoplatonists, the tendency to harmonize the doctrines of Plato and Aristotle was thus merely one harmonizing tendency among others. It arose out of two movements of thought … Pythagoreanizing Platonism … [which then] made Plato and Aristotle successors of Pythagoras, and the Platonism of Antiochus of Ascalon, which proclaimed the fundamental harmony between the doctrines of Plato's Academy, the Stoic school, and the school of Aristotle’ (p. 50).

The second part of the book's narrative addresses in more detail the philosophies and pertinent writings of particular Neoplatonists further to refine and argue for its thesis. In both parts, moreover, H. pays careful attention to previous scholarship pertinent to his topic and thesis. Conspicuously absent from his narrative, though, is analysis or even indication of where Porphyry's mentor Plotinus fits into the book's topic – for example, as may be gleaned from his Sixth Ennead and its treatises on being and number. This quibble aside, H.'s narrative and analyses highlight the diversity and plurality among the particular Neoplatonists not only with respect to how much, or to what degree, they discerned doctrinal harmony in Plato's and Aristotle's philosophies but also in their methodologies for discerning this. Thus, for example, we find Porphyry carefully critiquing (and criticising) Aristotelian doctrines regarding the soul to discern where Aristotle was correct (and so potentially in agreement with Plato) regarding the soul (pp. 56–8) whereas we find Stephanus of Alexandria purposively reading Aristotle in a manner which would agree with Platonic doctrine, proclaiming that ‘if he [Aristotle] spoke of an unwritten tablet … it is because it contains letters that are minuscule and invisible’ (p. 70).

Another important corollary to H.'s harmonisation thesis is the fact that, however much a particular Neoplatonist may discern Plato and Aristotle to ‘agree’, also a ‘recurrent feature in late Neoplatonism is the affirmation of the superiority of Plato over Aristotle in everything having to do with questions of metaphysics and theology’ (p. 52). Thus, for example, in reading Syranius we find ‘the distinction between an Aristotle who is more a philosopher of nature, and a Plato who is more of a theologian’ (p. 124). Or, in more general terms, among the Neoplatonists ‘the philosophy of Plato is considered to be higher, more theological, and more inspired as compared to that of Aristotle’ (p. 134) so that even ‘Aristotle's Metaphysics can only be an intermediary stage between the study of principles and natural causes and the true theology developed by Plato’ (p. 134). Even here, though, there is no single monolithic Neoplatonist viewpoint, as Simplicius, for example, maintained that in most cases of seeming differences between Plato and Aristotle ‘the difference between the philosophers is not over a reality, but over a name’ (p. 167); and David (Elias) counsels the exegete not to approach the philosophers’ texts as either a Peripatetic or a Platonist but to approach them as equals and not take sides (p. 141).

The book's concluding bibliography of previous scholarship and textual resources is also (again aside from Plotinus) quite thorough and useful.