Western European civilization has witnessed a sort of atomizing process, in which the individual is more and more set free from his natural setting in family and neighborhood, and becomes a sort of replaceable unit in the social machine. His nearest neighbors may not even know his name. He is free to move from place to place, from job to job, from acquaintance to acquaintance, and - if he has attained a high degree of emancipation - from wife to wife. He is in every context a more and more anonymous and replaceable part, the perfect incarnation of the rationalist conception of man. Wherever western civilization has spread in the past one hundred years, it has carried this atomizing process with it. Its characteristic product in Calcutta, Shanghai, or Johannesburg, is the modern city into which myriads of human beings, loosened from their old ties in village or tribe or caste, like grains of sand fretted by water from an ancient block of sandstone, are ceaselessly churned around in the whirlpool of the city - anonymous, identical, replaceable units. In such a situation, it is natural that men should long for some sort of real community, for men cannot be human without it. It is especially natural that Christians should reach out after that part of Christian doctrine which speaks of the true, God-given community, the Church of Jesus Christ. We have witnessed the appalling results of trying to go back to some sort of primitive collectivity based on the total control of the individual, down t o the depths of his spirit, by an all-powerful group. Yet we know that we cannot condemn this solution to the problem of man's loneliness if we have no other to offer. It is natural that men should ask with a greater eagerness than ever before, such questions as these: "Is there in truth a family of God on earth to which I can belong, a place where all men can be truly at home? If so, where is it to be found, what are its marks, and how is it related to, and distinguished from, the known communities of family, nation, and culture? What are its boundaries, its structure, its terms of membership? And how comes it that those who claim to be the spokesmen of that one holy fellowship are themselves at war with one another as to the fundamentals of its nature, and unable to agree to live together in unity and concord?" The breakdown of Christendom has forced such questions as these to the front. I think that there is no more urgent theological task than to try to give them plain and credible answers.