The momentous meeting of the World Council of Churches at Amsterdam in August focussed the attention of the world anew upon the question of church unity. The Bishop of the Episcopal Diocese of Washington has given us in this volume a characteristically thoughtful and deeply spiritual interpretation of the problems involved in moving toward a united church. He points out that in the Protestant denominations three principal concepts of the church are to be found. There is, first, the ""Catholic"" idea which conceives of the church as the work of God. Then, there is the ""classic"" Protestant viewpoint which finds its authority for the church in the word of God. Finally, there are the Protestant denominations which view the church primarily as a voluntary fellowship of those possessed of the spirit of God. The united church, the ""Great Church"" as Bishop Dun calls it must make room for all of these concepts. The chapters of this book represent the first series of lectures given under the Hoover Lectureship on Christian Unity established by the Disciples Divinity House at the University of Chicago. Bishop Dun has not written for the learned few but for the average Protestant minister and the thoughtful lay members of our churches.