The controversy between Barlaam the Calabrian monk and Gregory Palamas, the Byzantine monk and bishop, is often held to epitomise the differences between eastern Orthodox Christianity and that of the Latin west. Barlaam's condemnation by successive Byzantine synods is still enshrined in the last anathemas to be added to the Synodikon of Orthodoxy, still in principle proclaimed each year at the beginning of Orthodox Lent. Palamas, in contrast, was canonised by the Orthodox Church within a decade of his death. The terms of the controversy still cast their shadow over the scholarship of the period: for the most part, editions of Palamas and his supporters have been prepared by Orthodox scholars, whereas Barlaam and others who opposed Palamas have been edited (and generally rather better) by western scholars. Barlaam, in particular, has not lacked scholarly attention, and this edition of his letters replaces an edition made only half-a-century ago. As Fyrigos argues in his lengthy introduction there was no single controversy between Barlaam and Palamas: the first three of Barlaam's letters (including two lengthy letters to Palamas) relate to what Fyrigos calls the ‘Palamite controversy’ of 1334–5, which concerned the Filioque and the use of syllogistic logic in theology, both of which Barlaam opposed with arguments that were made welcome in the realm of Byzantine theology (especially through their use by Neilos Cabasilas, Palamas's successor in the see of Thessaloniki), despite Palamas's opposition to what he took to be Barlaam's position. The other five letters, all quite short, belong to the next decade and concern Barlaam's attack on the physical techniques used by the hesychast monks and their claims to experience of the uncreated light (the ‘hesychast polemic’, as Fyrigos puts it). In his introduction, Fyrigos provides a careful discussion of the manuscripts involved, the historical context of these letters and the light they shed on Barlaam's time in the Byzantine empire (he later returned to the west and, with the patronage of Petrarch at Avignon, acquired an episcopal see). In broad terms Fyrigos can be said to reflect the general scholarly consensus, though there are details that will still invite discussion (for instance, over what it was of Barlaam that Palamas was attacking in the earlier controversy). Fyrigos also provides a very useful brief biography of Barlaam, a list of his works and editions of them, and a detailed bibliography – the kind of material one would have found in Conticelli's La Théologie byzantine et sa tradition (ii, 2002), had Barlaam been included in that work.