In this monograph David Gwynn deconstructs Athanasius' description of his opponents as a collective heretical party, which he branded ‘the Eusebians’ and accused of ‘Arianism’. Gwynn concludes that ‘the Eusebians’ were neither a ‘party’ nor ‘Arian,’ and that Athanasius' depiction of the fourth-century Church as polarised between his own ‘orthodoxy’ and the ‘Arianism’ of ‘the Eusebians’ is a polemical construct the distortions of which must be recognised if we wish to understand the fourth-century Church. Meticulously researched and cogently argued, Gwynn's book is essential reading for scholars of the period. It is divided into three parts. In the first part (chapter i), Gwynn establishes the chronology of the works in which Athanasius presents his construction of ‘the Eusebians’, in order accurately to trace the development of his polemic. In so doing, he provides his readership with a thorough survey of the status questionis regarding the dating of some fifteen Athanasian writings. In the second part (chapters ii–iv), Gwynn traces the origins and development of Athanasius' polemical construct. He holds that the polemic emerged when Athanasius began to present his own condemnation at the Council of Tyre in 335 as the consequence of the machinations of ‘the Eusebians’, an ecclesiastical party headed by Eusebius of Nicomedia and dedicated to promoting ‘Arianism’. In the third part (chapters v–vii), Gwynn tests the political and theological veracity of Athanasius' construct. He shows that Athanasius presents the ‘Eusebian’ party as a group which had collectively abandoned the true Church and its ‘orthodoxy’ as defended by him in order to follow the teachings of Arius. Its membership, as defined by Athanasius, shifted over time and according to his polemical purposes, enabling him to present all his opponents from the 330s to the late 350s as representatives of a single heretical party. Gwynn then analyses whether the actions of those whom Athanasius calls ‘the Eusebians’ provide any evidence for a unified political agenda of a single ecclesiastical party against Athanasius and his ‘orthodox’ supporters. Given the fragmentary non-Athanasian evidence for many of these activities, the results here are largely inconclusive. In the last, and longest, chapter, Gwynn determines whether ‘the Eusebians’ subscribed to ‘Arian’ theology. He first defines what he calls ‘Athanasian Arianism,’ that is, how Athanasius himself presented the theological views of Arius and his supporters. Gwynn then compares this theological construct to the known views of specific ‘Eusebians’, Arius, Asterius, Eusebius of Nicomedia, as well as to the Second Creed of the Dedication Council of Antioch in 341, maintaining that neither these ‘Eusebians’ nor the creed reflects an ‘Athanasian Arian’ theology. Gwynn then concludes that the ‘Eusebians’ did not exist as a distinct ecclesiastical party except in the polemic of Athanasius and that the monolithic ‘Arianism’ imputed to them by Athanasius does not do justice to their distinctive theologies. This is not to deny that the so-called ‘Eusebians’ shared political and theological concerns; it is to realise that Athanasius' polemic distorts the reality. Gwynn's monograph notes but does not address why Athanasius's polemical construct found widespread acceptance.