Dreams - What They Are and How They are Caused
by C.W. Leadbeater
1898

1903. The Mechanism-Physical, Etheric, and Astral; The Ego; The Condition of Sleep; Dream Visions; Symbolic, Prophetic, True, Vivid, and Confused Dreams; Experiments.

Excerpt from book:

Sleepers may be observed at all stages, from this condition of all but blank oblivion, up to full and perfect consciousness on the astral plane, though this latter is naturally comparatively rare. Even a man who is sufficiently awake to meet not infrequently with important experiences in this higher life, may yet be (and often is) unable so far to dominate his brain as to check its current of inconsequent thought-pictures and impress upon it instead what he wishes it to recollect; and thus when his physical body awakes he may have only the most confused memory, or no memory at all, of what has really happened to him. And this is a pity, for he may meet with much that is of the greatest interest and importance to him.
Not only may he visit distant scenes of surpassing beauty, but he may meet and exchange ideas with friends, either living or departed, who happen to be equally awake on the astral plane. He may be fortunate enough to encounter those who know far more than he does, and may receive warning or instruction from them, he may, on the other hand, be privileged to help and comfort some who know less than himself. He may come into contact with non-human entities of various kinds — with nature-spirits, artificial elementals, or even, though very rarely, with Devas; he will be subject to all kinds of influences, good or evil, strengthening or terrifying.

But whether he remembers anything when physically awake or not, the ego who is fully or even partially conscious of his surroundings on the astral plane is beginning to enter into his heritage of powers which far transcend those he possesses down here; for his consciousness when thus liberated from the physical body has very remarkable possibilities. His measure of time and space is so entirely different from that which we use in waking life, that from our view it seems as though neither time nor space existed for him.