From the orphanage of George Muller in the nineteenth century to the biblical scholarship of F. F. Bruce in the twentieth, the Open Brethren in Britain have exercised a profound influence on the practice and piety of worldwide Evangelicalism. Though they have suffered from a measure of scholarly neglect, this has been remedied gradually over the last several decades. In the first comprehensive history of the Brethren to take the new scholarly literature into account, Tim Grass has provided a path-breaking and definitive survey of the movement in Britain that is accessible, scholarly, broad in scope and judicious in judgement. Grass tells the story of the Open Brethren over the last 200 years, recounting in rich detail the evolution of the movement through four different phases from its beginnings and consolidation in the nineteenth century to its withdrawal and decline in the twentieth century. At each stage, he is careful to place the movement in a wider context, giving special attention to its relationship with broader trends in Evangelicalism as well as society, culture and politics. Throughout his narrative, Grass is attentive to the problem of identity within the movement. He argues that the distinctiveness of the Open Brethren can be found in the unique combination of six prominent characteristics. These include commitment to the sole authority of Scripture, dedication to overseas and home mission, practice of believer's baptism, emphasis on the primacy of the lord's supper in weekly worship, rejection of the distinction between clergy and laity, and stress on the autonomy of local assemblies. It will surprise some that neither pre-millennial eschatology nor separatism make Grass's list of distinctives, but he provides compelling reasons for these omissions. Though each of these features have played an important role in shaping Open Brethren thought and practice at various stages, Grass makes a solid case for seeing them as salient but contested commitments the importance of which never went unquestioned and has waned over time. In light of this discussion of distinctiveness, Grass offers a tentative prognosis about the future prospects of the movement that is refreshingly optimistic. In Grass's opinion, since separatist ecclesiology and pre-millennial eschatology have always been intertwined, the decline of the popularity of the latter amongst Brethren in recent times should open the way for a reconsideration of separation and a restoration of the movement's vision for unity. After offering a few suggestions on the reform of Open Brethren thought and practice in light of his preceding historical analysis, Grass concludes that the flexible congregational ecclesiology of the Brethren and their critique of the mainstream Church's tendency towards institutionalisation represents a perennial theological theme in Christian history and one that still has much to offer the Church catholic. Grass's work should commend itself to a wide readership.