The curches` engagement in social, political and economic life, in the form of both action and reflection, has been a marked emphasis of the twentieth-century ecumenical movement. Yet many people are unaware of the origins and development of ecumenical social thought; and no single concise account of that history has been published. This volume is intented to fill that gap. It surveys ecumenical social thought from its early roots in the mid-19th century, examines and compares three key ecumenical concepts of society ("Responsible Society", "Just, Participatory and Sustainable Society" and "Justice, Peace and the Integrity of Creation") and then introduces major areas of ecumenical social thought, including international affairs, human rights, peace and development, by way of brief key quotations from authoritative ecumenical documents. Following an overview of Roman Catholic social thought, a final chapter offers an evaluation of how ecumenical social thought has developed and suggest some of the challenges and prespects facing it in the future.