Korey D. Maas's The Reformation and Robert Barnes is a timely reassessment of Martin Luther's English friend and fellow reformer. A meticulously researched biography (pp. 9–67) is followed by a balanced assessment of Barnes's theology (pp. 71–164), and a thorough analysis of the later reception of his thought (pp. 167–226). Maas challenges the view of earlier commentators that Barnes merely represented ‘the standard Lutheran thesis’ (p. 63), and points to the subtle differences between Luther and Barnes on the eucharist (pp. 50–7) and authority (pp. 58–68) in order to buttress his case. In these, and many other instances, Maas significantly expands on 1960s and ’70s studies. Where scholars previously restricted themselves to an examination of Barnes's two vernacular writings, Maas analyses Barnes's writings on the basis of their content, not their language. Because of his extensive use of primary sources, Maas is able to explain why earlier commentators previously failed to recognise the reformer's ‘historical bent’ (p. 167): Barnes's historical-theological programme is, in fact, ‘most discernible in his Latin works’ (p. 167). The largest, and most exciting, part of the work is devoted to tracing and outlining this historical-theological programme in the four treatises that Barnes wrote between 1530 and 1536 (pp. 71–164). In them, the reformer attempted to answer one of the most pressing questions of the time: ‘Where was your Church before Luther?’ For an answer, Maas in particular turns to Barnes's final work, the apology Vitae romanorum pontificum, published in Wittenberg in 1536 with a preface by Luther. Barnes was convinced that the Roman Church had no claims over Luther's movement. Following his detailed investigation of the historicity of Roman doctrines and practices to substantiate his claims, his conclusion is that of a historian rather than that of a polemicist. Where contemporary polemicists condemned the Roman pope as the ‘AntiChrist’, Barnes pointed to the all too human foundation of the Roman Church: ‘The pope and his papacy came into the Church of God only by cunning and by desperate efforts … and boasted to be constituted by divine right’ (‘subdole & perditis studiis Papatum suum Papa Ecclesiae Dei intruserit … iure divino cum Papatum iactarint esse constitutum’: Vitae, A 8 r). Barnes pioneered a methodology that was just as important as his conclusion. Maas claims that Barnes was able to make use of his ‘distinctive understanding of the relationship between scripture, history, and the theological and polemical use of each’ to excellent effect precisely because he had a definite historical-theological programme (p. 146). This is a tremendous monograph: well-researched, reliably informed, rigorously referenced and carefully nuanced. Maas not only succeeds in providing a much needed new assessment of the English Lutheran and his historical-theological programme, but opens up many new and exciting avenues for future research.