The World Council of Churches was deeply involved in selecting the editions and writers of these volumes. The aim was to provide a systematic survey of the ecumenical history of the churches in the from of a sober and impartial account of the many ecumenical impulses, initiatives and activities during the centuries covered. Taking the Reformation as its starting point, the first volume covers four centuries of varied endeavours towards church unity in Europe and North America. In particular it deals with the Faith and Order, World Mission and Evangelism, and Life and Work movements in the twentieth century, which led to the formation of the WCC in 1948.