THE attempt to hold intercourse with the inhabitants of the unseen world is not, as some seem to imagine, a practice peculiar to these modern times. It was resorted to long before the Greeks inquired of Apollo in his temple at Delphi through the mouth of the Pythoness and before the Romans consulted the Sibylline oracles at Cumae and at Tibur. Nor is it a practice confined to civilized and cultivated races. The savage man, too, in his lonely hut on his desert island, has at all times been in the habit of evoking the spirits of the other world, whether he believed these spirits to be genii, disposed to favour and to benefit mankind, demons bent on working harm or mischief, or the souls of the dead seeking for rest amidst their former haunts and environments History records how extensively spiritistic practices were carried on during the middle ages, and what severe laws, both civil and ecclesiastical, had to be enacted in order to check what was then held to be a dangerous and harmful superstition. The object of this book is to set forth: as clearly and concisely as possible, what the teaching of Catholic Theology is on this difficult subject, and where the pathway of safety may be found, not only for Catholics but for all believers in historic and dogmatic Christianity. For it is in the historic Christian Faith alone that we have the true standard by which the momentous problems presented by modern spiritism can be fairly and adequately judged. Our object then will be to discover whether, according to this standard, we can reasonably hold the belief that we are, by means of these spiritistic practices, really put in communication with the spirits of the dead, and whether we may look upon these communications as containing newer and truer disclosures as to the spirit-world and to spirit-life, and as to history and science and the general moral and intellectual progress of mankind. We shall endeavour to set forth in these pages, as faithfully and as clearly as possible, what the teaching of the Fathers and Doctors reflecting the mind of the Catholic Church is on this deeply important subject, and shall draw our deductions from those fundamental principles upon which the laws of the universe are founded, submitting each statement to the judgment of the Church, which is "the pillar and ground of the truth." The phenomena shown to be taking place in connection with recent experimental research are, as is well known, many and wonderful, and the problems presented by them are of the greatest possible importance and significance. It is only the serious study of them, in the light of Catholic Theology, which can lead the inquiring mind to a discovery of the real agents responsible for Their production, and enable it to determine the question as to the lawfulness and morality of spiritistic practices.