THIS book, which was published in 1759, is one of the most important works of Saint Alphonsus. He himself explains what it has cost him, and the value that he sets upon it. In his preface to the" Preparation for Death," he speaks thus: "This book, though small, has cost me a great deal of labor. I regard it as of extreme utility to all sorts of persons; and I unhesitatingly assert that among all spiritual treatises, there is none, and there can be none, more necessary than that which treats on prayer as a means of obtaining eternal salvation."Saint Alphonsus gives the plan of his work: "In order, then, to attach ourselves to this great means of salvation, we must first of all consider how necessary it is to us, and how powerful it is to obtain for us all the graces that we can desire from God, if we know how to ask for them as we ought. Hence, in the first part, we will speak first of the necessity and power of prayer; and next, of the conditions necessary to make it efficacious with God. Then, in the second part, we will show that the grace of prayer is given to all ; and there we will treat of the manner in which grace ordinarily operates."Saint Alphonsus begins: "ONE of the errors of Pelagian ism was the assertion that prayer is not necessary for salvation. Pelagius, the impious author of that heresy, said that man will only be damned for neglecting to know the truths necessary to be learned. How astonishing! St. Augustine said: "Pelagius discussed everything except how to pray," though, as the saint held and taught, prayer is the only means of acquiring the science of the saints; according to the text of St. James: 'If any man want wisdom, let him ask of God, Who giveth abundantly, and upbraideth not.' The Scriptures are clear enough in pointing out how necessary it is to pray, if we would be saved."Further on we read: "We will, as we promised, demonstrate that the grace of prayer is given to all men. But this doctrine does not please Jansenius; he goes so far as to call it an hallucination: "It is an hallucination to think that the grace of prayer is always present to a man." According to his system, he considers that without the delectation relatively victorious we cannot pray; but this delight is not granted to all men, therefore (he adds) all men have not sufficient grace and power to fulfil the commandments; for many are without even the remote grace to enable them to pray as they ought, or indeed to pray at all. "Since, therefore," he continues, "most men either do not ask for grace to enable them to fulfil the law, or do not ask for it as is necessary; and since God does not give all men the grace either to pray fervently, or even to pray at all, it is most evident that many of the faithful are without that sufficient grace, and, consequently, without that perpetual power of fulfilling the one precept (of the moment) which some theologians proclaim," Before, then, we prove our own position, we must confute his pernicious system, from which all his errors are derived; and we must show that not we, Imt that he is laboring under an hallucination."