The appearance of this book simultaneously with the opening of the Second Vatican Council is most fortuitous. Here is a very ironic approach to Church unity written by a Roman Catholic, who is aware of both the position of his own communion, and the standards to which those outside Rome have repaired. The book is full of surprises for both Roman and non-Roman readers. There is a careful appraisal of the World Council of Churches. There is a realization that no Church, not even a very large one, can speak for the whole Church, and that the true development of Christian faith and understanding await the day when the Church speaks with a united voice. The careful reasoning of Brother Thurian probably limits his audience to people with some knowledge of the ecumenical movement, but nothing more technical puts the book beyond the reach of an intelligent layman. Best of all, the book is written to be read by all participants in the ecumenical conversations. Roman, Anglicas, Orthodox, Protestant and Sectarian. All will be enlightened by this presentation of the extent to which tradition is a base on which unity can be .