The author describes the processes which led to the founding of the World Council of Churches (W.C.C.) at Amsterdam in 1948. The foundation is seen as a long journey of parallel movements on the international scene which eventually converge to form the Council. The article deals not only with the sociological and institutional elements of the W.C.C. but also with the more important ecclesiological issues which undergird the organization. In the second part of the article the A. points out some of those documents of the W.C.C. which are imnortant for the understanding of the Council and its workings and which articulate a sort of «self-definition». (pp. 61-74).