Wesleyan-Holiness Churches in Australia is a welcome addition to the published resources on Methodism in the South Pacific. In this 242-page hardcover, Glen O'Brien explores the arrival of Holiness denominations in Australia that arose out of American Methodist and Pentecostal heritage in the twentieth century. He provides a much-needed overview of four groups in particular: the Wesleyan Methodist Church, the Church of the Nazarene, the Church of God (Anderson), and the Church of God (Cleveland). O'Brien's historical summary feeds into analytical and philosophical discussions about the groups' distinctives and practices. The writing style is easy-reading, while the conclusions are meaningful and thought-provoking.There has been a noticeable lack of Methodist historical publications emanating from Australia, New Zealand, and the island-nations of the South Pacific since the early twentieth century, with only a handful of publications specifically addressing the reasons for mainline Methodism's declining vitality. O'Brien's work as co-editor and contributor to Methodism in Australia: A History (2015) and this more recent publication, Wesleyan-Holiness Churches in Australia (2018), has been a real service to both academic and private readership. The material covered in this current volume has been largely available within the specific denominational circles, but not easily accessible to wider readership. O'Brien's research draws these records together in a format that will aid the broader Holiness-Methodist-Pentecostal readership to understand each other better and to discover a shared history. An example of these ‘missing links’ can be seen in O'Brien's reference to Doug and Maysie Pinch (index, 241). Pinch's ministry in the Wesleyan Methodist Church from 1964 to 1978 has been covered in other sources, but O'Brien references his ministry with the Nazarenes from 1946 to 1963 (84) and with the Church of God (Anderson) for many years (167).1 This topic of movement between the Wesleyan-Holiness denominations is not often explored, though it has been a fairly common phenomenon.While these historical details are of special interest to denominational readers, O'Brien's broader commentary and discussion of social and church growth dynamics render his book useful to a global audience. His discussion of the interface between Holiness and Pentecostal denominations is tantalizing and his reference to anti-American sentiment in post–Second World War Australia delves into a topic that other nations may have similarly encountered. I was personally drawn to O'Brien's conclusion that if the American Holiness denominations had come to Australia in the 1920s rather than the post-War 1940s, they ‘may have been able to capitalize on what was left of the Methodist interest in holiness and of the Keswick Convention movement’ (75). Of course, as O'Brien has noted, there were some attempts in these earlier decades (chapter 3). Perhaps the outcome of A. B. Carson's ministry (68–71) might suggest that, while Australia may have been open to holiness teaching in the 1920s, the cultural legalism of American teaching still overshadowed the holiness message and was not appealing to the Australian market. It would be interesting to further explore this thesis in light of the impact of Howard Guinness's visits in the 1920s and 1930s with Inter-Varsity Fellowship and the Evangelical Union. Guinness promoted a strong holiness message, and his ministry created a lasting impact, for better or for worse.In summary, I have found O'Brien's work, Wesleyan-Holiness Churches in Australia, thoughtful, informative, and credible. I recommend it to other students of church history and to any who would seek to better understand the differences and commonalities within the Methodist-Holiness-Pentecostal families. I congratulate Glen O'Brien for his efforts in producing such a useful publication.