Fernando Enns, Professor of Mennonite Peace Theology and Ethics at the University of Amsterdam has recently published a new book Ökumene und Frieden (Ecumenism and Peace). In it Enns shows how ecumenism “works.” What are realistic goals and methodologies? Enns applies the ecumenical approach to different fields of theology and ethics. The large chapter on the Ecumenical “Decade to Overcome Violence” of the World Council of Churches is the first coherent account on that stimulating enterprise.