The Church today must exist in a world that is, if not openly hostile, indifferent to the Christian faith. This book provides a frank and trenchant outline of the way in which in the societies of the West the consciousness of modern man with his vestigial Christianity has been transformed by discoveries such as the electronic computor and the manned space satellite, and by developments such as the Welfare State and the mass media that manipulate the minds of millions. After showing how far advanced in a world that must become a unity or perish are the forces of dechristianization, desacralization and atheism, the authors describe the movement of self-renewal that is stirring at the very heart of the Church today. They discuss new missionary methods that have been and must be devised to meet the twentieth century including worker priests, adaptation to non-European cultures and the abandonment of many non-essential traditions that have previously been identified with the Church. They conclude with a challenge: "Each man is a mission territory. The missionary problem lies within the conscience of every Christian".