Robert Crookall - The techniques of astral projection

From Introduction: In every period of man's history some people have claimed to have had an experience that to others was pure fantasy-they claimed to have left their physical bodies in a second body (a non- physical one which they variously called the "Astral", "Etheric", "Spirit", t'Spiritual", "Soul", "Four-dimensional", etc. Body) and declared that they thought, felt, saw, heard, and acted in it. These out-of-the-body experiences are popularly called astral projections on the assumption that an objective "Astral Body"was, in fact, projected from, or released by, the familiar physical body. St Paul (2 Cor. xii, .) mentioned a case of this kind and many reputable people, including Roman Catholic Saints and Quakers, have had such experiences.
The existence of out-of-the-body experiences, then, is certain: what is in doubt is the exact nature of the "Astral Body", i.e. whether it is always a hallucination (a mental image) or whether it is sometimes a "real", objective (though non-physical) body. In some instances there was doubtless nothing whatever of an objective nature-the supposed "Astral Body" was merely imagined. But if, in other instances, an objective body was involved, the matter is of very great importance to us all.

In 1961 I cited a hundred and sixty first-hand descriptions of out-of-the-body experiences in a book entitled THe Study and Practice of Astral Projection (Aquarian Press). In the conclusions (p. 140) I advanced reasons for concluding that many of the "Astral Bodies" there described had not been imagined but were "real" and objective. Over two hundred further cases are given in a book entitled More Astral Projections shortly to be published by Aquarian Press. Many point to the same conclusion. If the latter is justified, then the probability that we survive the death of the physical body is very great-the "Astral", "Etheric" or "Soul" Body would, in fact, be the mechanism of survival.