IT has been said that, in the history of the Church, the twentieth century will eventually be known as the century of the laity. And it must be admitted that probably at no preceding epoch have there been the same opportunity and need for the co-operation of the faithful laity in the defence of the Church, in the promotion of her interests and in the "pacific penetration," by means of their example and intellectual influence, of the society in which they live. But it may be said with equal truth that our century is also the century of retreats. And this is just what we should expect in the ordinary course of Divine Providence. That our Catholic laity, of both sexes and of all social classes, should be fitted, always under the direction and control of ecclesiastical authority, to play the magnificent role which is awaiting them, it is absolutely necessary, not only that they should have a thorough training in Christian Doctrine and in the knowledge of all that appertains to their religion and its history, which is obtained by a good Catholic education and by the reading of Catholic literature; but also that they should have frequent opportunities for what is called, even outside our own body, the" deepening of the spiritual life." It is not mere knowledge of the Faith, of the Church's constitution and her history, however extensive and accurate, but also, or rather far more, the intensity of, the spiritual life and the application of religious principles to everyday practice, that will enable the Christian layman and laywoman not only to save their own souls, but to play their part great or small in saving the world around them. And this all-necessary "deepening of the spiritual life" is the work of retreats for the people. We may thank God for this "great revival" which Father Plater so admirably describes in the present volume. It is, indeed, a wonderful and inspiring story. As I wrote on another occasion: "Never before have these invaluable aids to salvation been so freely accessible to all classes and all ages of the Faithful. But a few years ago a retreat was a spiritual luxury within the reach only of the clergy, the religious, and the leisured and well-to-do classes. Nowadays, thanks to institutions like the Cenacle Convents in Manchester, London, and Liverpool, for women and girls, and Oakwood Hall, Romiley, for men, all classes of Catholics, down to the very poorest, and all ages, from married persons to little children preparing for their' first Communion, can at least in this part of England--secure the full advantages of a retreat with the greatest facility and at very moderate expense.' If the results, social as well as religious, produced by the workmen's retreats in Catholic Belgium are as yet far beyond anything we can aspire to in this country, still the progress which has been made in this direction during the past six years is certainly most gratifying. Father Plater's modesty does not allow him to state that the first public impulse given to the movement was the admirable paper read by himself at the Brighton Conference of the Catholic Truth Society as late as 1906. What has happened since is narrated by his own pen in the following pages. But I feel it to be a mere act of justice on my part, whilst expressing my appreciation of this book and my earnest desire that it may be widely read by both Catholics and non-Catholics, to record here how very greatly the whole movement is indebted to the author, both for its inception and its subsequent development, which he has never ceased to further by both pen and voice, by articles and by lectures. Yet, whatever share Father Plater and so many other devoted men and women have been privileged to have in this divine work, none will be more ready than they to protest: "I have planted, Apollo watered; but God gave the increase. . . . For we are God's coadjutors." (I Cor. iii. 6, 9.)