This biography provides an exploration of the formative influences, development, and impact of the theology of David Smith Cairns, Scottish minister, academic, and writer, during the high point of British imperial expansion, and at a time of social tension caused by industrialization. It describes and evaluates his role in the Church's efforts to face major challenges relating to its relationships to the different world religions, its response to the First World War, and its attitude to the scientific disciplines that called into question some of its longstanding perceptions and suppositions. An eminent figure, born into the United Presbyterian Church and rooted in the Church in Scotland, Cairns operated ecumenically and internationally. His apologetics challenged the prevailing assumptions of the day: that science provided the only intellectually legitimate means of exploring the world, and that scientific determinism ruled out the Christian conception of the world as governed by providence. A major feature of his theology was the presentation of Christianity as a ""reasonable"" faith, and throughout his life he maintained a particular concern for young people, having endured his own crisis of faith when a student in Edinburgh. He enjoyed a decades-long involvement with the World Student Christian Federation, based on a mutually enriching relationship with one of its leading figures, the renowned American evangelist John Raleigh Mott. ""Dr. Finlayson has given us a superb account of the life and times of D. S. Cairns, arguably the most influential Scottish theologian of the early twentieth century. Best known for his seminal report on inter-religious dialogue for the Edinburgh World Mission Conference of 1910, Cairns also produced important studies of religion and science, and drafted the classic study of belief amid the carnage of the First World War, The Army and Religion."" --Stewart J. Brown, Professor of Ecclesiastical History, University of Edinburgh ""In this clear and scholarly study of D. S. Cairns, Marlene Finlayson has provided a welcome exploration of Scottish theology and church life in the early twentieth century. In particular, her discussion of the contribution of Cairns to the World Mission Conference of 1910 and his subsequent reflections on the impact of the Great War will be of much interest to a wide readership in ecumenical and historical theology. We are indebted to Dr. Finlayson for her coverage of an important European figure too long neglected in the scholarly literature."" --David Fergusson, Professor of Divinity, University of Edinburgh Marlene Elizabeth Finlayson is a graduate of the University of Edinburgh, member of the Iona Community, Church of Scotland elder, and board member of Interfaith Scotland. She left a career in teaching young children to pursue some of the theological and spiritual questions that have engaged and absorbed her attention over the years. This book is a product of that continuing search that every generation of Christians must make for itself.