The author has long been associated with the Ecumenical movement of the Christian churches as they seek to find a way of reunion. He seeks to advance the thesis that this unity will be carried forward if the thought of the inseparable unity between Christ and His church is illuminated and clarified. If the church is the Body of Christ, as most Christian denominations believe, on Biblican and theological grounds, then it is simply a contradiction to speak about several churches. If the unity of the church is dissolved into a plurality, this means that the connection between Christ and the church is broken,- the church ceases to be the church. This contradiction between the unity which is grounded in the essence of the church and what we see in the church's actual situation has come more and more to be recognized in our generation as a contradiction that must be resolved. ""...As Christ is a part of the Gospel and is its real content, and as the church, by reason of its unity with Christ, belongs also to the Gospel, new light falls on the unity that is sought."" It is this light which the author seeks to make brighter by a cogent, Biblical exposition of the subject. The book will be important to all who share a growing concern that the church must be one if it is to be the church in the New Testament sense of the word. It is not an easy nor ""popular"" book, but many will find it of great interest, clergy and laity alike.