Most cultures throughout the world and throughout history have conceived of the existence of spirit worlds, astral dimensions were the souls of the dead would travel, but that could also be visited by the living by inducing altered states of consciousness. As varied as accounts of astral projection have been from one culture to the next, all variations on the more or less universal phenomenon of the individual subconscious mind's connection to the "Universal Mind" or collective unconscious.
Ancient Paganism & Shamanism
Most of the lore from ancient pagan and shamanistic cultures contains mythical conceptions of a vertical world tree, mountain, or axis. By induction of trance states a shaman could project his consciousness up or down such a structure to visit the spirit worlds. The Germanic mythological worlds of the Aesir and Vanir, the Elves, Night Dwarves, and Giants (among others) are descriptive of astral realms, as are the Celtic Faery World, Middle Kingdom, and the "land under the hill." In these worlds the shaman could change his shape, often into one of the same kind of beasts that accompanied him as a familiar spirit. Often the shaman and his spirits were also charged with battling other tribes and repelling their magick.
Pagan Germanic sagas are filled with accounts of warriors, witches and sorcerers projecting their astral bodies, often in the form of animals. The god Odin himself was described astral projecting and shapeshifting in the Ynglinga Saga, which described how he would lie inert in a hypnotic trance "as if dead, or asleep; but then he would be in shape of a fish, or worm, or bird, or beast, and be off in a twinkling to distant lands upon his own or other people's business."
Hermeticism & Neoplatonism
In some cultures — notably the more advanced pagan societies where the Hermetic and Neoplatonic schools of thought took hold — the symbolic structures tree or pole structures representing a world axis were also associated with the concept of a "chain of being." An emanation of divine energy begins from its source — sometimes conceptualized as a supreme being or "source consciousness — and emanates down through progressively more dense vibrational states (planes or spheres) into the lower incarnate forms of matter (densely concentrated energy).
According to the Neoplatonic and Hermetic traditions, the physical dimension was one of the densest and lowest planes. The astral realms are an intermediate series of dimensions between the earth sphere and the higher spiritual dimension. The Neoplatonist Proclus was evidently the first to use the term "plane" to refer to these dimensions. Usually in the Hermetic, Gnostic, and later medieval alchemical literature, these are conceived in schematics involving a series of concentric circles representing the spheres associated with the planets and stars, each of which is populated by various spirits (including angels, demons, pagan gods, etc.). The "world of planetary spheres" was crossed by a soul (in its astral body) on its ascension or on its way to rebirth. Many other traditions believe that recently deceased individuals enter the astral planes and incarnate in astral forms in order to work out the results of past actions in their prior incarnation on the physical plane.
The Medieval Era & Paracelsus
Despite the noteworthy contributions of occultists such as Paracelsus, Agrippa, and Faust, the discussion and practice of occultism and magick (including astral projection) was inhibited during this era due to the oppression of the Church. Open attempts to practice astral projection were generally only tolerated when undertaken by the clergy or individuals recognized by the Church as saints. Otherwise it tended to be condemned as either a delusional or diabolical practice, most obviously in the case of witches who were put on trial for engaging in the process, along with various charges of the use of malicious witchcraft.
Abbot Trithemius was one notable clergyman thoroughly steeped in the overt practice of magick and the occult, while denouncing occultists such as Faust for engaging in the same practices. Writing on the subject of alchemical transmutations, Trithemius mentions the projection of the astral body, saying that "...you must know how to separate spirit and life in Nature, and, moreover, to separate the astral soul in yourself and to make it tangible, and then the substance of the soul will appear visibly and tangibly, rendered objective by the power of the spirit."
One of the most enduring contributions to the rebirth of occultism in the Germanic world came from the ingenious medieval physician and alchemist Paracelsus, who expounded on the "astrum" and "astral light" in great detail in his writings. Paracelsus said that it was possible to project consciousness anywhere in the universe via the astral medium, which permeates everything. One of his main points of emphasis was the relationship between the astral and physical bodies and the importance of these dynamics in preventing or healing diseases and other afflictions. The writings of Paracelsus were very influential to many of the most influential occultists of later eras.
John Dee & Edward Kelley
In the 16th century the Elizabethan Renaissance man and special agent John Dee and the rogue alchemist Edward Kelley undertook their extensive scrying operations, depending heavily on the self-hypnotic abilities of Kelley. Dee apparently presented himself as a devout Christian convincingly enough to escape serious persecution by the Church, although Dee and Kelley still received negative attention for their overtly occult undertakings.
Dee and Kelley did not give any accounts of full "out of body" astral projection experiences, but were remarkably successful at opening the gateways to the astral dimensions through Kelley's autohypnotic Mind's Eye visions, which he obtained by scrying in a crystal "shewstone." Through this process they established contact with a group of spirits claiming to be the same "angels" who communicated with the biblical Enoch. The true agenda of these spirits is uncertain (to say the least) but through their astral communications Dee and Kelley received many pieces of an extraordinarily complex system of magick, including an entire speakable, writeable, and translatable language. During these operations, neither the spirits nor the astral landscapes in which they resided remained contained completely within the crystal, but would sometimes appear in various parts of the chamber. Talented scryers of ancient and modern times alike will most likely be familiar with this phenomenon.
The Occult Christianity of Swedenborg and Blake
After the Protestant "Reformation," the Church began to lose its stranglehold over the priestcraft's supposed intermediary role between the earthly and spiritual realms, and more accounts of astral projection began to be openly recorded. In the 1700s the Swedish scientist Emanuel Swedenborg practiced astral projection extensively, and visited realms inhabited by spirits and angels. He used his experiences as the basis for a new branch of mystical Christianity, which he founded in London.
A generation after Swedenborg, William Blake also had extensive astral visions and journeys into astral dimensions related to Christian mythology. He was visited by spirits identifying themselves as angels and commented that most of his poetry was effortlessly received from the angels, and was merely transcribed by himself. Like Swedenborg, Blake believed the angels had chosen him to bring God's teachings to the rest of humanity, and he and his wife later joined Swedenborg's Church.
Spiritualism, Theosophy and the Modern Occult Revival
In the 19th century a popular craze for conducting seances rose out of what was otherwise the height of the materialist age. While the popularity of conducting seances attracted many frauds who used tricks to produce phenomena such as table-rapping, the ability to communicate with spirits has long been known to not only to many individuals with a natural talent for autohypnosis. Such persons were known as "trance mediums" during the spiritualist era.
Interest in spiritualism gave rise to a corresponding interest in the study of the astral body. Hereward Carrington made a thorough study of a young man named Sylvan Muldoon for this purpose. Muldoon had a natural talent for astral projection but still correctly identified self-hypnotic techniques as the operative technique for the projection of the astral body. The spiritualist Allan Kardec also used autohypnosis to evoke the shade of Saint Alphonsus, who had been reputed to have an outstanding grasp of astral projection in his time. Whether the spirit that appeared to Kardec was actually that of Saint Alphonsus, the shade gave sound advice to Kardec on the practice of astral projection.
The Theosophical society which was also active in the same era produced a great deal of literature on the theory of the astral planes but generally had little to say about how to accomplish it. The exception was the English Theosophist Oliver Fox. Fox had a natural aptitude to slide into the deep autohypnotic trance states that facilitate the projection of the astral body, and these had often terrified him as a child. He experienced astral projection both as travels "out of the body," and as astral visions in which he remained in the body but had visions of creatures ranging from horrific monsters to gnomes or faeries. Fox also discovered the ability to project the astral body of out of the Third Eye energy center. He called this technique "the Pineal Doorway."
Remote Viewing: Astral Projection Repackaged by Psychic Spies and the CIA
In the early 1920s and 30s, Soviet scientists such as Leningrad's Leonid L. Vasiliev proved the reality of telepathic hypnosis, including the subconscious mind's transcendence of spatial distances. The discoveries of Vasiliev and other Soviet scientists investigating parapsychology (under the assumption that a materialistic cause would be found to explain them) led to a substantial amount of research behind the Iron Curtain. In the 1960s and 70s more reports of Soviet research into parapsychology began to leak out and reach major newspapers, and Western intelligence agencies eventually became concerned. A Defense Intelligence Report on "Controlled Offensive Behavior Research in the Soviet Union" concluded that: "Many scientists, U.S. and Soviet, feel that parapsychology can be harnessed to create conditions where one can alter or manipulate the minds of others. The major impetus behind the Soviet drive to harness the possible capabilities of telepathic communication, telekinetic and bionics are said to come from the Soviet military and the KGB."
In response, the CIA began to employ parapsychological researchers such as the Stanford Research Institute's Harold Puthoff and physicist Russell Targ, who performed tightly controlled laboratory experiments on "remote viewing." The attempt to use astral projection for this purpose was researched under a program known as "Project Stargate." The remote viewers called the practice "Extended Remote Viewing," and used autohypnosis to accomplish it. They began by inducing a hypnotic theta trance state through deep physical relaxation, which they called "the cool-down process." The remote viewer would then construct his own astral sanctuary using visualization as a staging zone, after which they would project to their intended target.
The remote viewers discovered that they could access the deep well of information that can be drawn out of the collective unconscious, commonly called the "Akashic records." The remote viewers called this well of information "The Matrix," and found that it contained information about their targets. However, while the accuracy of some of the information was totally uncanny and could not be explained by chance, it was often imperfect and contained errors. The CIA later officially discontinued the program on the grounds that the information obtained by remote viewing wasn't reliable enough to base a complete military action, although the reality of the phenomenon itself was never questioned and the commissioned report confirmed that the remote viewers were consistently obtaining statistically significant results in the laboratory.
Modern Astral Projection
Knowledge concerning astral projection has proliferated dramatically in modern times, largely due to the much wider availability of information in modern times, as well as the inability of the priestcraft of the major monotheistic religions to effectively continue their campaign to eliminate or suppress esoteric knowledge.
So many modern authors have now written on the subject of astral projection that there are too many to discuss in detail. One of the most significant pioneers in the early 20th century was the American businessman Robert Monroe, an executive with a natural talent for the practice. Monroe wrote several books on "out of the body" experiences," a term he popularized in reference to astral projection. Monroe was also involved with pioneering research and development into audio brainwave entrainment to guide the brain into the trance states that facilitate projection. Another major modern writer on astral projection is Robert Bruce, whose extensive research over several decades in conjunction with other astral voyagers led to his accumulation of a large body of methodical techniques for accomplishing astral projection and activating the Mind's Eye to see into astral dimensions.
While the practice can hardly be termed mainstream at this time, the wide availability of knowledge on how to successfully accomplish astral projection has caused a huge increase in the number of individuals independently verifying the reality of the phenomenon. Those who either object to the practice or who do not want it to exist for various reasons have consequently been obliged to move way from overt denial, and change instead to declaring that astral voyagers are hallucinating or mentally unstable, or else to proclaim that the practice constitutes a religious offense.