Suetonius (Aug. 94.12) reports that Octavian's fascination with astrology began while still a youth in Apollonia. Thereafter astrology's credibility in Rome increased along with Octavian's authority. For Augustan authors, this meant that the stars were now on the literary agenda. Yet, Steven Green argues, their treatment of astrology must respond to the emperor's contradictory attitudes towards it, for astrology was an object of both imperial enthusiasm and imperial concern. In a tripartite study, he identifies the different strategies authors employed to accomplish the difficult task of attending to both responses simultaneously.

G. begins by looking closely at the five books of Manilius' didactic poem Astronomica. He traces the cumulative educational experience of the Reader — that is, the audience the work imagines — and the real readers. Enthusiasm to learn the tenets of astrology turns to despair as the books progress, for the information provided is confusing, contradictory and incomplete: no one could cast a horoscope based on Manilius' instructions. This observation is not new, but G.'s interpretation of this unsuccessful lesson is. He argues that the Reader's two outbursts in Book 4 declaring confused frustration point to Manilius' intent to provide not an ‘incomplete lesson’ in the manner of other didactic poems but rather a ‘failed lesson’, the result of ‘an embedded strategy of misdirection’ (60) adopted to navigate the emperor's ambivalence towards astrology. As a poet expounding the powers of astrology, Manilius must keep critical mechanics hidden in order to glorify, to please and to protect the poem's imperial addressee, who is imagined ‘sitting quietly, in the background, appreciating Manilius’ novel enterprise' (59).

The location of astrology in the political context of the late Republic is the focus of the second section. G. discusses Caesar's comet of 44 b.c. as a pivotal point for astrology. No longer a mere object of academic curiosity, henceforth astrology would be a political presence. The sceptical élite would learn to be discreet: juxtaposing Cicero's discussions of astrology in De divinatione, written just before the appearance of the comet, and De fato, perhaps completed after this event, G. detects a politically prudent ‘softening’ of attitude towards astrology.

The final section comprises a series of studies, the first of which applies to Augustus' traditional ways of thinking about astrology and politics, to conclude that ‘astrology seems primarily to have been a piece of political craft that was both essential and dangerous to him’ (107). Subsequent chapters consider how Augustan authors besides Manilius dealt with astrology under the looming shadow of a hypocritical emperor. Vitruvius and Virgil concede authority to astrology as a science, but counsel that it is best left to foreign specialists, while Horace's injunction (Carm. 1.11) not to seek the date of one's death is advice given anxiously rather than philosophically. Both Hyginus and Ovid promise to expound details about astrology, but abort the programme. Other authors explored the safe topics of the stars' effects on the weather, the nature of Caesar's comet or the tricks of unskilled astrologers. It is not until the time of Hadrian that philosophical criticism of astrology can once again be voiced with full confidence of imperial tolerance.

Many of G.'s arguments are ingenious, but they can only be as convincing as the foundations upon which they rest are stable. The proliferation of astrological specialists vitiates the possibility that astrology was widely considered a do-it-yourself project. It is doubtful that serious students of the science would seek out instruction in the technicalities from a five-book didactic poem. Discreet handling of astrology's secrets by Manilius surely did not ensure that others were keeping them, and so imperial appreciation of Manilius' attempt to cork the gun of astrology seems pointless amidst a blaze of cannons. But was astrology really deemed a weapon, much less a singular weapon? Imperial interest in astrology is certain; less sure is imperial fear of astrology or hypocrisy about its use. An aura of truth has settled upon the long-standing assumption that the science of astrology constituted an especially anxiety-causing imperial preoccupation. Yet to maintain this assumption G. must interpret the evidence selectively or depend upon supposition. A few examples: Augustus' prohibition against consulting manteis about death in a.d. 11 (Dio 56.25.5) is rendered a narrow injunction against genethiological astrology (102–3); but one should note that single-minded fervour for astrology is called into question by the evidence of Manilius himself, who hopes that as much credibility will attach to it as already clings to augury and haruspicy (4.911–14). So that Octavian's behaviour can be characterized as hypocritical, G. proposes 44 b.c. as the year in which he published his horoscope since there is ‘nothing … to rule out the possibility’ (74; cf. 103). Argument becomes circular when G. suggests a date for the completion of De fato in order to demonstrate the transformative effect of Caesar's comet (87).

Cracking the frame of imperial anxiety does not, however, remove all value from G.'s discussion. On the contrary, many of the chapters, particularly of the third section, remain interesting studies of how Augustan authors dealt with the science that attracted imperial enthusiasm but in which they were inexpert. G. self-consciously transposes contemporary attention to ‘student experience’ to his readings, but a second instructive modern parallel is discernible in the need of intellectuals to attend to the interests of patrons and funding bodies.