Archbishop Felix Machado has been a professor of Interreligious Dialogue and Ecumenism. He has worked as Official for Religions in Asia and Undersecretary in the Pontifical Council for Interreligious Dialogue, Vatican, from 1993 to 2008. This book is a response to God’s grace and a deep desire to realize the unity Christ willed for the Church and the world. Consequently, given the vast scholarship that has gone into its making, it will undoubtedly be a milestone on our ecumenical roadmap. It is based on the teachings, guidelines and norms of the documents of the Church that have shaped the Catholic Church’s engagement in seeking Christian unity. This work is a mine of information for ecumenists, professors and students of ecumenism, will also be very useful to the lay reader who desires to understand in greater depth the mind and the engagement of the Church in this vital area of apostolate.