The ecumenical movement of the 20th century was a quest for unity born of a missionary concern for the world. Thus, from the beginning of present-day ecumenism, mission has been inextricably linked with unity. This volume explores the themes of unity, mission, and their relationship. Seventeen Roman Catholic and Protestant scholars offer essays in honour of George Vandervelde, a leading evangelical ecumenist from the Reformed tradition.

Jesus' prayer on behalf of his of followers is "that all may be one. As you, Father are in me and I am in you, may they also be one in us" (John 17:21). No Turning Back illustrates significant developments in ecumenism during the thirty-plus years of ecumenical theologian Margaret O'Gara's own engagement in ecumenical dialogue. This collection of selected papers from the final fifteen years of O'Gara's work before her untimely death in 2012 aims to illustrate the broad lines of ecumenism for general readers to share concrete details of recent ecumenical developments with specialist readers to encourage both groups of readers in their commitment to the pursuit of full communion among the Christian churches An invaluable resource for academic and ecclesial specialists in ecumenism, teachers and students of theology and religious studies, Christian ministers, and all educated Christian adults who take seriously Jesus' prayer "that all may be one."