Starting, then, not from savage authority, but from the evidential scrutiny of modern facts, we shall find, I think, that there are coincidences of dream with truth which neither pure chance nor any subconscious mentation of an ordinary kind will adequately explain. We shall find that there is a perception of concealed material objects or of distant scenes and also a perception of a communion with the thoughts and emotions of other minds. Both these phenomena have been noted sporadically in many ages and countries, and were observed with serious attention especially by the early French mesmerists. The first group of phenomena was called _clairvoyance_ or _lucidité_, and the second _communication de pensées_, or in English, _thought-transference_. These terms are scarcely comprehensive enough to satisfy a more systematic study. The distant perception is not _optical_, nor is it confined even to the apparent sense of sight alone. It extends to all the senses, and includes also impressions hardly referable to any special sense. Similarly the communication between distant persons is not a transference of thought alone, but of emotion, of motor impulses, and of many impressions not easy to define. I ventured in 1882 to suggest the wider terms _telæsthesia_, sensation at a distance, and _telepathy_, fellow-feeling at a distance, and shall use these words in the present work. But I am far from assuming that these terms correspond with definite and dearly separated groups of phenomena, or comprise the whole field of supernormal faculty. On the contrary, I think it probable that the facts of the metetherial world are far more complex than the facts of the material world; and the ways in which spirits perceive and communicate, apart from fleshly organisms, are subtler and more varied than any perception or communication which we know. I have halted above at another line of demarcation which the dreamer's own sensations suggest,--the distinction between active psychical excursion or invasion and the passive reception of psychical invasion from without. But even here, as was also hinted, a clear line of division is hard to draw. For whether we are dealing with dream-perceptions of distant material scenes, or of distant living persons, or of discarnate spirits, it is often impossible for the dreamer himself to say either from what point he is himself observing, or where the scene of the vision is laid. For the present I must confine myself to a brief sketch of some of the main types of supernormal dreams, arranged in a kind of ascending order. I shall begin with such dreams as primarily suggest a kind of heightening or extension of the dreamer's own innate perceptive powers, as exercised on the world around him. And I shall end with dreams which suggest his entrance into a spiritual world, where commerce with incarnate or discarnate spirits is subject no longer to the conditions of earthly thought.