Since the publication of Marianne Jehle-Wildberger's monumental biography of Adolf Keller in 2008 there has been a modest revival of interest in this once conspicuous, and yet soon dolefully neglected, pioneer of the international ecumenical movement. Keller's many virtuoso qualities aside, his contribution was often devoted to bringing together the theological and ecclesiastical worlds of central Europe and the English-speaking world, and in this he certainly achieved much, not least in his formidable, cross-border philanthropic activities. The present volume represents the fruits of a conference and the opening and closing addresses offered by church dignitaries frame five solid contributions by Emidio Campi (on Keller's role in the formation of the Schweizerischen Evangelischen Kirchenbundes), Stefan Grotefeld (on Keller's contribution as both a Swiss and an international thinker on social ethics), Harald Matern (on Keller's thought on ecclesiology and politics), Marianne Jehle-Wildberger (on Keller as a figure caught in relation to Jung and Barth, both of whom he knew well) and Dagmar Heller (on Keller's legacies as they have influenced the subsequent work of the Ecumenical Institute at Bossey). Beside the essay by the admirable Stefan Grotefeld, Harald Matern's article is particularly illuminating, placing Keller firmly in his own particular milieu – and what a milieu it was – and showing how he sought to pursue the creative possibilities of diversity across the Churches as they actually inhabited the political world of his own day. In short, Keller was no abstract, academic theologian but essentially a contextual thinker, a Christian internationalist hopefully at work in the age of the League of Nations, and an active participant in events and affairs at large. Perhaps the fact that he was a man so rooted in his own age has limited his appeal to later theologians. Yet, if that is so, he is surely a figure who should be all the more important to historians. Much still needs to be done to uncover the bustling world in which he turned up, time and again, across a long and laudable life.