This book will be useful for readers who want to know more about the ecumenism of some American Protestant ministers around the turn of the twentieth century. The historian David Mislin uses the writings and sermons of prominent theologians who helped make a more inclusive approach to non-Protestant religions into a way ‘to save American faith’, allegedly under threat from secularisation and modernity (p. 7). His claim that such ministers as Lyman Abbot, Charles Briggs and Washington Gladden actually ‘began’ the religious pluralism that Mislin conflates with ecumenism overlooks an expanse of important American religious history, and in general the argumentation of the book extends beyond the reach of its evidence, but it is helpful for Mislin to amplify the voices of these ecumenical leaders. Mislin seems to fall for their talk of Christian union when they woo Catholics to forget the Reformation; they were hardly laying down their Protestantism and rejoining the papal fold. Instead, while it is not true pluralism to propose that the League of Nations ‘be leavened with the truth of Christ’, as the Federal Council of Churches did (p. 135) – hence their contentious debates over whether Unitarians should be allowed (p. 118), a tension Mislin does not explore as his category ‘liberal Protestant’ goes unexplained – the book vividly introduces episodes like the fantasy of rapprochement with the Catholics, pulpit exchanges between rabbis and ministers in Detroit (p. 149), and the World's Parliament of Religions held at the Columbian Exposition in Chicago in 1893. Mislin's selective reading in the secondary and primary literature around this and other ecumenical episodes provides a bright and clear picture of religious vitality in modernising America. ‘The lesson most Protestants had learned over the previous decades’, Mislin writes, ‘was that religious pluralism was something to be celebrated, not eliminated’ (p. 138). Although it was surely only some Protestants who learned this rather than the Evangelical most, this shift toward engagement, interest and even celebration of diverse approaches to religious faith and practice merits readers’ attention.