To those who know nothing of, or who doubt everything, about the spirit world, this series of teachings will have no meaning; but to the students of psychical phenomena and supernormal development this practical treatise will be timely and providential. No work of inspiration is sent to earth without a purpose. The needs, the aspirations, the sufferings of humanity evoke the ministrations of spirits and depth and height meet, as it were, by a law of cause and effect, science has not as yet explained.