In this book you will therefore find wholesome instruction, great knowledge of the interior life, and of the human heart, - the result of years of experience in the direction of souls. The subject is at once both highly important and very difficult. The Author has not confined himself to general principles and vague maxims, but he has entered into the very sanctuary of the soul, into its secret folds and most intricate windings. The thread of Reason, the light of Faith, and the torch of Experience have led him safely through that labyrinth where so many lose themselves, rashly attempting to explore it without the proper guides. A few principles, presented under different aspects, solve all difficulties, throw light upon doubts that are ever recurring, expose all the subterfuges of self-love, sloth, and cowardice, refute their objections, and silence their excuses. The Author has followed the most useful plan for works of this kind. He adopts the method of reasoning - and his reasoning is as clear as it is solid. The greater number of persons who profess piety prefer appeals to their imagination and to their heart, rather than to their reason. They like to be excited by lively descriptions, and by tender and touching language; but in so doing, they are seeking a passing gratification rather than a real and permanent benefit. Such descriptions and sentiments soon fade away, but the fruits of conviction are more lasting. Pure reason and true faith never vary; imagination and feeling are incessantly changing according to the different objects which act upon them. It is from indolence that feeling is preferred to reasoning. The greater part of mankind are indolent, and hence there are so few who care to reflect and reason. But one who has an earnest love for virtue and duty, who is anxious about his salvation, should not shrink from the mental effort which the exercise of reason and of faith requires. We should remember that no sincere and permanent resolution can be taken without a conviction of its necessity. This is accorditlg to the natural order of reason, and to the economy of grace. The understanding must be enlightened before the will can be moved. This work appears to be specially intended for the instruction of persons living in religious communities, and for seculars aiming at perfection; but in this age of indifference and discouragement all who profess the true faith may here find no little help to undeceive them in their errors, and to strengthen them against the wiles of self-love. We venture to hope that even Directors of consciences may discover therein that which will increase their light, and supply for any want of experience in their difficult and dangerous ministry.