"There can be no uncertainty with regard to this; but the intermediate steps through which we must pass are not so clearly defined, I have often had occasion to speak of the possession by man of the astral and mental bodies, and of the development within some of us of the senses of these bodies, so that they have become what is commonly called clairvoyant. Those who possess these faculties now are those who have turned their attention especially to them either in this life or in some previous existence; but the faculties are undoubtedly the heritage of every human being, and there is no question that the race is moving steadily towards their fuller development. I have explained in the concluding chapter of The Other Side of Death how the man who wishes for the use of these faculties may proceed to unfold them within himself."