Sylvan J. Muldoon (February 18, 1903 – October 1969) was an American writer on the subject of Astral projection, a paranormal or occult term which usually refers to a consciously induced out-of-body experience or OBE. He claimed to have his first OBE when he was just 12 years old and often in a state of catalepsy. The experiences continued into his adult life. In 1927 he contacted Hereward Carrington after reading a book Carrington had written on astral projection, in the letter he states "What puzzles me most is that you make the remark that M. Lancelin has told practically all that is known on the subject. Why, Mr Carrington, I have never read Lancelin's work, but if you have given the gist of it in your book, then I can write a book on the things that Lancelin does not know!". This resulted in a partnership and work on The Projection of the Astral Body, which was published in 1929.
While the collection presented in this book is dated, most of the occurrences happening about a hundred years ago, the details of each person seem to be very similar—which I would argue, lends credence. While some admitted to having an interest in such things, others were actually horrified that what they experienced in the moment was death. The subject presented in this book appears to be as timeless as humanity; there have been contemporary accounts which detail methods used to promote astral projections. Fascinating stuff. Some of the usual symptoms were a state of cataleptics including tingling, vibrations, and according to those who were found by others, they claimed the subject was cool to the touch. Apparently, during such astral travels, respirations are reduced to the minimum. There were also claims that some sort of etheric cord connected the physical—emanating from the lower chest—to the spiritual—emanating from the base of the skull. Odd, that. I mean, who would make up such details? There was a movie made some years ago which presented this connecting cord pretty well; the name of the film is Donnie Darko. It's one of those movies, once watched, should probably be viewed a second time because the way it ends changes the viewer's perception of what happened in the whole movie. I'm not sure what to think about astral projection. I don't think I've ever quite experienced such a thing and, well, as they say: seeing is believing. But it sounds like the kind of fun you can't get with a visit to Disney...
Sylvan Muldoon, both an experiencer and a student of astral projection, presents dozens of short case histories from people in various walks of life who have experienced the "exteriorization" of their astral body from their physical body. Some are by people who already have spiritualistic beliefs; many others are by people who had never given such matters a thought. Muldoon notes that the broad similarity of the experiences points to their being something actual and worthy of proper scientific study. Sounds reasonable to me. The implications are as big as can be for us all. For interesting and recent scientific investigation into the existence of "subtle matter" (that is, the ether of which astral bodies are presumably made), check out The Discovery of Subtle Matter by Klaus Volkamer, published in 2017.