On the one hand, a study of poetic quotations in Chrysippus seems a worthwhile endeavour; for after all, according to several testimonies, the use and interpretation of poetry plays a central role in this Stoic's discourse. On the other hand, it seems a nearly impossible endeavour, as Chrysippus is only preserved via the indirect tradition – so one has to handle the fact that the excerptors have obliterated the original citation technique. Nevertheless, in the present book, which emerged from a dissertation at Vienna, R. attempts to undertake this worthwhile and almost impossible endeavour – and, let it be said in advance, he succeeds with this careful study. R. sets out the dilemma just indicated in the introduction: those fragments in which poetry quotations are found come from three sources, and each brings with it certain difficulties (especially, in startling density, p. 42): Galenus is the most important source for quotations on Chrysippus’ doctrine of the soul and affects, but he places them in his own context and selects them accordingly. The situation is even more complex in the case of the Epicurean Diogenianus, who is only preserved in excerpts from the Christian Eusebius in his Praeparatio Evangelica – thus Chrysippus can only be glimpsed in double refraction. Finally, in Plutarch's De Stoicorum repugnantiis (pp. 45–6) the quotations from Chrysippus are obviously based on the premise of proving logical breaks in his argument, i.e. they are a priori tendentious.

R. aims to do justice to this situation with a clear methodology. This refers in particular to the concept and terminology of the quotation: R. speaks of the four elements of the quotation (‘Die vier Elemente des Zitats’), referring to the pre-text (‘Prätext’), the subsequent text (‘Folgetext’), the quotation segment (‘Zitatsegment’) and the marking (‘Markierung’). This creates a clear operational model and integrates the study into a series of other recent works on the morphology and function of quotations in philosophical discourse, although the designation of the marking as an element (‘Element’) or constituent (‘Bestandteil’) of the quotation is perhaps somewhat unfortunate: the follow-up text, the pre-text and the quotation segment are textual in character, whereas the marking is rather a metatextual descriptive criterion: it can be textually reflected in a constituent (e.g. ‘Homer says: …’), but it can also consist in the conscious absence of any textual marker and/or be limited to the retention or removal of disturbing interferences (e.g. hexameter or poetic language in prose). It would be clearer to speak of the marking as a criterion of analysis.

The core of the book consists of three chapters dedicated to the authors who mainly transmit the fragments of Chrysippus: Plutarch, Galenus and Diogenianus. The conceptual structure of the Plutarch chapter is well thought out, but somewhat unexpected: while the introduction focuses on Stoic. rep., it is not followed by a presentation and analysis of the citation material for the purpose of deduction, but rather by an anticipatory inductive arrangement of the material according to the guiding techniques of citation: repetition (multiple use of the same quotation segment), expansion of meaning (here R., pp. 101–3, admirably corrects the understanding of Plut. poet. aud. 34b5 τὴν δ’ ἐπὶ πλέον τῶν λεγομένων χρῆσιν ὑπέδειξεν ὀρθῶς ὁ Χρύσιππος that is common in research: what is meant by ἐπὶ πλέον χρῆσις is not a generalisation, but a transfer, extension or expansion), correction (as an intervention in the wording to clarify what is meant in the subsequent text) and change of speaker (a quotation is intentionally assigned to another speaker). The basic problem of indirect access is shown once again in Stoic. rep. 47, where Plutarch, in order to construct a contradiction, draws together several passages containing poetic quotations from different works of Chrysippus, partly with modifications (pp. 134–40).

The chapter on quotations preserved by Galenus begins with the quaestio vexata, which work is meant when Diogenes Laertius (7.180) says that Chrysippus had reproduced in one of his writings practically the whole of Euripides’ Medea (ἔν τινι τῶν συγγραμμάτων παρ' ὀλίγον τὴν Εὐριπίδου Μήδειαν ὅλην παρετίθετο), adding the anecdote that a reader of this work, when asked about his reading, replied: Χρυσίππου Μήδειαν. Less pointed, but nevertheless sober and convincing, is the answer R. gives to the question: the enigmatic reading is in any case not identical with the writings by Chrysippus Περὶ ψυχῆς and Περὶ παθῶν used by Galenus. The next passage is also much debated – Galenus reproduces verbatim a passage from Chrysippus’ Περὶ ψυχῆς, where the latter quotes and interprets the Hesiodean account of the birth of Athena from the head of Zeus (SVF II 908–9). R. does not want to let this passage be undifferentiated as allegory; instead, he recognises a continuity in the citation technique, but also a special position, since here the symbolic interpretation of the poet's text becomes the object of reflection. For SVF III 473 (here R. identifies hitherto unrecognised structures from Chrysippus in the rendering by Galenus) and 478, both from Περὶ παθῶν, R. works out the argumentative relevance and close integration of the poet's quotations into the context. From SVF III 466, where Galenus reproduces Chrysippus after Poseidonius, R. extrapolates the interesting distinction between the citation introductions ταῦτα for a concrete and unique and τοιαῦτα for an exemplary poetic statement.

The third part of the work is devoted to the fragments from Chrysippus’ Περὶ εἱμαρμένης, which Diogenianus quotes, in turn preserved by Eusebius (Praep. ev. 6.8). Despite this complex transmission situation, R. arrives at a clear picture: Diogenianus interprets a series of Homer quotations that Chrysippus had used in a separate section consisting of evidence (in this R. recognises a second technique of use for quotations besides the direct integration into the primary chain of argumentation), within the framework of his inactivity argument directed against the concept of Stoic εἱμαρμένη (‘Untätigkeitsargument’, i.e. if everything is controlled by fatum, an individual will refrain from any activity as meaningless), contrary to the sense in which Chrysippus had invoked it. The summary shows once again what proves to be R.'s strength throughout the book, namely the ability to arrive at results that may not always be spectacular but are convincing and innovative in their coherence in complex contexts and without succumbing to the temptation of rash broad-brush statement. Significant stimulus seems to me to derive in particular from the following observations: the ancient statements that Chrysippus makes rich use of poetry are confirmed in their tendency. An important principle for the citation of poetry is πιθανόν, i.e. the use of poetry not as scientific proof in the proper sense, but in order to derive the habitual or customary nature of a statement. R. finds the techniques of expansion of meaning, shifting of meaning, repetition, correction and change of speaker, which were worked out on the basis of the speeches in Plutarch, confirmed for the entire corpus.

An overall result is that we should speak of symbolic rather than allegorical interpretation. In the course of the work R. pays a great deal of attention to the citation segments and pre-contexts – here, a synopsis, a look at Chrysippus’ library and when and where he reaches for which author might have been fruitful. But the index of passages, which helps to open up the impassable terrain that R. has traversed, offers a substitute. On the whole, R. presents an exemplary study. It not only underlines how omnipresent and significant poetic quotations are in the philosophical discourse of antiquity, but also what helpful insights can be gained from a systematic and methodically conscious investigation of this phenomenon.