REVEREND FATHER, The Holy Father has confided to me the agreeable mission of conveying to you his warm and sincere thanks for the remarkable treatise on Mystical Theology entitled: Les Graces d'Oraison, the fifth edition of which you have just published. His Holiness is rejoiced at the fruitful result of your long years of study, spent in observing the ways of grace in souls aspiring to perfection. He is happy to see that now, thanks to you, directors of consciences possess a work of great worth and high utility. You not only rely upon the incontestable doctrine of the olel masters who have treated this very difficult subject, but you present these teachings, which constitute your authorities, under the form that our age requires. While wishing your work a great success and abundant spiritual fruits, His Holiness grants to your Paternity the Apostolic Benediction. In acquainting you with this favour, I am happy to assure you of the sentiments of high esteem with which I am, Yours very affectionately in the Lord, CARDINAL MERRY DEL VAL. ROME, April 2, 1907. Father Poulain's book is an example of modern scientific methods applied to a subject-mysticism-which critics outside the Church commonly regard as a mere form of brain-weakness peculiar to pious persons, and over which even Catholics are sometimes apt to shake their heads. Is there to be found in the interior life of devout souls, in their intercourse with their Maker, a life more intimate still-a secret door opening into a world still further withdrawn from sense, where very few may enter, but where the chosen ones have a sight and ieeling of God, and enjoy His presence not less, but more really than we apprehend objects with our bodily senses? This is clearly a question of no little importance, and one which should not be without interest for a day like our own when we hear so much of Occultism and Theosophy and Spiritualism in its different branches-all of them attempts in their own way to pass material bounds and explore the region beyond. Pere Poulain's book is much more than an examination of spiritual marvels. It is a survey of the Kingdom of Prayer in all its length and breadth, in its lowest as well as its most perfect forms. The interior life is seen to be a process, an orderly evolution, of which we can outline the laws and mark the successive stages. Even in its highest development we are permitted, as it were, to watch the first sprouting of the wings, then their gradual growth and freer play, until at last, with gathered strength and unerring aim, they bear the soul towards God beyond the range of our sight. There are comparatively few problems of the ascetical life which do not fall in some degree within the scope of this treatise-the helps and hindrances of prayer, interior trials, scruples, discouragement, presumption. On all these topics the teaching of the author, deduced, be it observed, from the words or actions of the saints which he cites, seems to us eminently helpful and sane. Not unfrequently it lurks in unexpected places, in what appear to be casual remarks, in brief comments on some unusual point of theory or practice, but it will not escape the eye of a careful reader; and, above all, it will be treasured by those who are entrusted in whatever way with that most difficult and delicate of tasks, the direction of souls. The experiences of those who have climbed the highest peaks of Perfection, their successes, even their mistakes, cannot fail to be useful even to those who are still stumbling on its lower slopes, or only gazing wistfully upwards from its base.