Varieties of Ecclesial Unity explores ecumenical transformations in contemporary church history and theology. In the second half of the twentieth century, following World War Two, the work towards more Christian unity and ecclesial cooperation became one of the central tasks of church leadership and theological research. The book considers the shift to unity in faith and practice, how the legacy of this ecumenical approach is no longer certain, and whether the sentiment of unifying reconciliation has a future. In today’s context there are many new questions about the plurality of Christianity and new challenges to the idea of unity itself. The author reflects on how the unity of the universal church was understood in the ecumenical movement, and how it provides an alternative vision to war and nationalism today. He also offers a new proposal for thinking about the reconciliation of difference based upon multiple conceptions of unity rather than a singular theory or concept. The book is relevant to scholars of Christian theology, church history and ecclesiology, as well as others with an interest in ecumenism and peacebuilding.