This is not a book to be read hastily, but rather an aid to action. It was not undertaken with the idea that the reader skim through it in one reading. Rather, it should be carried over into life. Sincere readers who wish to practice the art of prayer correctly should, as the reading progresses, apply it to themselves. To be acceptable for publication, the book had to be abridged by one-half. It is full of repetitions and tedious passages. My plan has been to follow the soul through the different stages of the life of prayer, and at each stage to furnish it with a maximum of practicable, basic principles for its spiritual advancement. I have done this even at the risk of offering an excess of details, which would most assuredly be irksome were the book intended to be read in one sitting. All of these stages, moreover, resemble one another in certain aspects. Hence, repetitions were necessary if each reader was to find not only what applies to his particular case but also the exact way in which it applies. Each one may then extract what he needs. This method of procedure, however, could lead some souls into the pitfall of trying to apply all these suggested practices at once. Were they to do this, they would become confused and would soon find themselves overburdened. All I have done is to offer suggestions. If I have presented an abundance of them, my only intention was to give the reader a choice. It is up to each one to take what is applicable to him and what he can reasonably shoulder, always leaving himself free to take on more as he progresses. Prayer is a complex art with many nuances where progress is not only slow but requires as much prudence as it does diligence. In the present volume I have limited myself to the ordinary forms of prayer. To explore the relationship which exists between ordinary prayer and mystical prayer would have been an interesting study, but the book would have assumed such proportions that it seemed preferable to defer the study of mystical prayer for a second work which will be directed to an entirely different class of readers. I offer this book to the modern public with some apprehension. It is no way flatters modern tendencies nor does it lay claim to any novelty. By preference, it is based on the foundations of time-tested traditions. The style is so simple that it can be understood by the most unlearned, and that at the risk of appearing to be somewhat puerile. Having this sacrificed art for utility, it is my fond prayer that this book will nonetheless bear much fruit, and that even its very shortcomings will help men of good will to find God in prayer.