The volume deals with introductory methods and aspects in philosophical writings (six contributions), Christian texts (one contribution), medical writings (one contribution), astronomical texts (one contribution) and musical writings (two contributions, including the appendix). The aim is to show that the study of isagogical aspects in texts belonging to different disciplines sheds light on the interaction between these disciplines and reveals that this interaction had both methodological and theoretical implications. The volume opens with a useful, chapter-long introduction, in which the editors not only present the purpose and background of the book but also specify what one can find at the crossroads of these different texts, namely recurrent formal features and the attempt ‘to establish … or transmit a body of knowledge’ (p. 12). The editors acknowledge previous scholarship on the topic, most notably, J. Mansfeld's Prolegomena. Questions to Be Settled Before the Study of an Author, or a Text (1994) and his Prolegomena Mathematica (1998), and they are aware of the criticisms that these works have received. This leads primarily to a nuanced treatment of the topic. Yet, it also leads to some vagueness, for example when it comes to the question whether isagogics is a literary genre (compare p. 1: ‘difficult to define it as a literary genre’; p. 3: ‘genre’ in quotation marks; p. 10: ‘isagogics is not only a literary genre in itself’).

In Chapter 1 Petrucci explores isagogical concepts among Peripatetics from the first century bce to the second century ce. After a brief look at non-Peripatetic isagogical texts on Aristotle's philosophy from that period, he focuses on Peripatetic commentaries, or testimonies thereof, before Alexander. He argues, in line with preceding scholarship, that, although there is no evidence for isagogical schemata, it is possible to detect isagogical elements. He concludes that pre-Alexandrian Peripatetic commentaries already anticipated many of the isagogical questions that we can find in later Neoplatonic commentaries. It would have been interesting to read more about Alexander of Aphrodisias, or about Petrucci's motivation for leaving out Alexander's commentaries in a study on post-Hellenistic Peripatetic exegesis.

In Chapter 2 F. Ferrari discusses isagogical elements in Diogenes Laertius, On Plato, Book 3 of his Lives, against the background of the systematisation of Platonic philosophy among Platonists between the first century bce and the third century ce. He gives an excellent overview of this process of systematisation, the problems that those authors faced and the strategies that they applied. By focusing on Diogenes’ exposition of the nature and order of the Platonic dialogues, Ferrari carefully analyses both the typological and the tetralogical classification of Plato's writings, the λύσις ἐκ προσώπου and the three-stage exegetical procedure. Although Mansfeld (1994) examines these aspects too, Ferrari's analysis is a valuable addition, also because his focus lies on the process of systematisation. Ferrari shows that these aspects have both an isagogical and a systematising function. He concludes that Book 3 includes the most refined overview of isagogical schemata with regard to Plato's works that is still extant from the period prior to the Neoplatonic commentaries, being a witness of, and a source for, the process of systematising Platonic philosophy.

In Chapter 3 J.A. Stover examines the title, composition and content of Apuleius’ De Platone. The chapter goes far beyond the question as to whether the work is an isagoge, as the title suggests. It continues Stover's previous work on the topic (especially A New Work by Apuleius. The Lost Third Book of the De Platone [2016]) and will be of interest to scholars working on Apuleius in general. By analysing the manuscript tradition, Stover questions the title and the composition of the work, suggesting that ‘corpus’ in its different senses might have been the structuring principle of the work (‘De Platone 1 – Plato's physical body; De Platone 1–2 – Plato's doctrinal body; De Platone 3 – Plato's literary body’, p. 69). This, in turn, leads to two interesting hypotheses, which Stover also advocated for in his previous work. First, the Platonic summaries might have constituted the third book, and second, in using this tripartition, Apuleius would follow a conventional pattern found in other contemporary isagogical texts.

In Chapter 4 I. Männlein-Robert deals with isagogical elements in Porphyry's Isagoge and his Vita Plotini. In addition to identifying these elements, Männlein-Robert is particularly interested in Porphyry's motivation for using them. She argues in line with previous scholarship that they serve both didactic and philosophical purposes. She identifies Porphyry's philosophical motives as follows: for the Isagoge they consist in the harmonisation between Plato and Aristotle and the goal of bridging the gap between middle Platonism and Plotinus’ Platonism. For the Vita Plotini Porphyry's motives are the elevation of Plotinus both philosophically and spiritually and the preparation of the reader for the intellectual orientation of Plotinus. What is particularly interesting in this analysis is a feature that her work is well known for, i.e. the attention to the influence of, or links to, Longinus’ work as well as to middle Platonism in general.

In Chapter 5 Motta focuses on the notion of taxis. She discusses the Stoic partition of philosophy and its influence on Platonism, especially on the order of Plato's dialogues in Neoplatonism. She argues that the question of the order of the parts stimulated the systematisation of Platonism. On the one hand, she explicates the distinction, and relation, between logical order and pedagogical order in both Stoicism and Platonism and argues that, while both coincide in, especially, Neoplatonism, they do not coincide in Stoicism. On the other hand, she analyses the roles of, and the relation between, logic and dialectic, supporting the well-known conclusion that, while dialectic is subordinated to logic in Stoicism, dialectic is metaphysically loaded and thus superordinated to logic in, especially, Neoplatonism. Both the explication of the two orders and the discussion of logic and dialectic explain (the development of) the different orders and their crucial differences.

In Chapter 6 G. Van Riel deals with a conflict in Proclus’ isagogical remarks in his Commentary on Plato's Timaeus and in his Platonic Theology. As Van Riel points out, in the course of his discussion of the double, i.e. Pythagorean and Socratic, character of Plato's Timaeus, Proclus describes the Pythagorean way of investigating as ‘proceeding in a symbolic and mystical fashion’ and lists as one of the Socratic characteristics the investigation of things through images (p. 113). In his Platonic Theology, however, the first characteristic is ascribed to the Orphic Hymns and the second to the Pythagoreans (pp. 113–14). Van Riel argues that the incongruity is neither merely apparent nor did Proclus miss it, but rather that he accepted it for the sake of what he considered to be more important aspects. Van Riel explains Proclus’ motivation for accepting the incongruity by means of an excellent analysis of Proclus’ general interpretation of Plato's Timaeus.

With Chapter 7 the discussion moves from isagogical elements in ancient pagan philosophical texts to those in ancient Christian texts, and in particular to the pedagogical works of Eusebius of Caesarea. In the first part of his contribution, S. Morlet focuses on Eusebius’ General Elementary Introduction (GEI). Despite the difficult textual situation, Morlet succeeds not only in reconstructing the structure of the work in a plausible way but also, by means of a thorough analysis, in shedding light on the different isagogical patterns that the work contains. In the second part Morlet deals with the Praeparatio evangelica (PE) and the Demonstratio evangelica (DE) and compares their pedagogical aspects to those of the GEI. He pays particular attention to the question of the addressed audience and the question as to whether these texts were used as school handbooks or whether the pedagogical elements are ultimately based on literary considerations. Morlet argues carefully that it is rather unlikely that the GEI and the PE / DE were used as school handbooks.

In Chapter 8 G. Ecca examines the role of the Hippocratic Aphorismi in the late ancient medical curriculum. By means of a thorough analysis of the Aphorismi in late ancient commentaries and four independent texts on the first aphorism, Ecca argues convincingly that the Aphorismi played an important role as an introductory text in the late ancient medical curriculum. Moreover, she fruitfully compares this role with that of Galen's De sectis ad eos qui introducuntur, which was used as an introductory text to Galen's work. Consequently, she raises the question of the relationship between the Hippocratic and the Galenic curricula, drawing a parallel to the relationship between Plato's and Aristotle's writings in the late ancient philosophical curriculum.

In Chapter 9 V. Gysembergh focuses on the presence of isagogical questions in Hipparchus’ Commentary on the Phaenomena and, specifically, in the prefatory letter. He argues both that almost all the standard questions are addressed and that they are answered not only with regard to Aratus’ poem but also with regard to Hipparchus’ commentary. Unfortunately, Gysembergh's contribution is very short, and he lists, rather than examines or discusses, the answers provided in the text. One would have wished that the author had elaborated further on his findings.

In Chapter 10 E. Rocconi deals with musical introductions. She gives an excellent overview of (1) the different approaches to harmonics, (2) the kinds of didactic writings that evolved around it, (3) the writings entitled ‘introduction’ from the Roman imperial period that are still extant and (4) on what is known about earlier introductory works. Rocconi shows well that, although these ‘introductions’ differ in content and structure, they share clear isagogical patterns and contain all practical information and a reflection of oral teaching. In the last part of her rich contribution Rocconi pays particular attention to Cleonides’ Introduction to Harmonics and examines its relation to Aristoxenian harmonics. She concludes that the notion of ‘musical introduction’ was applied rather generally to introductory handbooks used in a teaching context. Moreover, she stresses that the way in which these texts were transmitted allows for the possibility that they were entitled ‘introduction’ only at a later stage.

The book includes an appendix in which A. Barker provides an introduction to and new English translation of Gaudentius’ Introduction to Harmonics. The introduction includes many valuable remarks, especially with regard to the general theme of the volume, i.e. its characterisation as an isagoge. The translation is more readable than T.J. Mathiesen's translation in O. Strunk and L. Treitler (edd.), Source Readings in Music Theory (1998), pp. 66–85. However, Mathiesen's translation will still be useful, especially for the notes that include references to other introductory texts to music, and for the restoration of the diagrams. Unfortunately, like Mathiesen's translation, Barker's translation is not accompanied by the Greek text.

On the whole, the volume contains contributions of high quality and constitutes a valuable addition to the studies on introductory patterns and schemata isagogica, most notably to those by Mansfeld.Footnote ¹