Christianity--and consequently the Church--is in a grave crisis, which mere penness will not surmount. Structures developed by the Church in the past lack the flexibility to meet radical change. The assumption that Christianity, and therefore the Church, has a fixed abode in the world which nothing can violate, will no longer do. Among the essential problems confronting the Church in this situation is that of rediscovering the meaning of catholicity, and to this problem Father Adolphs addresses this book. He traces the development of the concept of ""one holy catholic Church"" from its nception, near the end of the first century, pointing out that the concept soon became static and triumphalist,"" rather than dynamic--something not yet fully and finally given, ut given as a goal to be achieved. In discussing the impact of the Renaissance and the nformation upon this concept of catholicity, he calls for a new approach toward the information, and therefore toward Protestantism, that has been followed in the past. ""new morality,"" ecumenism, and Communism, all call for what he characterizes ad ""dia""--an openness toward the world, a willingness to listen, and to enter into dia The book is written with a restraint, but a freshness, realism, and courage, that should make it essential reading for both Protestants and Roman Catholics who are concerned for a new rapprochement in our time.