Astral projection is the practice, and claimed experience, of the consciousness or a subtle "astral body" separating from the physical body and travelling independently of it, whether through the ordinary world or through non-physical planes of existence. It belongs to the wider category of the out-of-body experience, and it is cultivated deliberately in a number of Western esoteric and New Age traditions, in which the practitioner uses techniques of relaxation, visualisation and induced trance, often from the threshold state between waking and sleep, to bring about the sensation of rising or slipping out of the body and moving about while it lies still. The idea of a soul or subtle body that can leave the physical form is very old and widespread, appearing in many cultures' accounts of the soul, of dreams and of the journeys of shamans and mystics, and it was systematised as a technique within the Theosophical and ceremonial-magical currents of the modern West.
The status of the experience is contested. Those who practise it generally hold that the astral body genuinely travels and may perceive real things at a distance, and the practice is valued as a means of exploration, spiritual development and encounter with other planes. Scientific investigation, by contrast, generally accounts for out-of-body experiences as products of the brain and mind, states in which the ordinary integration of bodily perception and self-location breaks down, producing the vivid sensation of being outside the body without any actual separation, and controlled attempts to verify the perception of distant information during such experiences have not yielded reliable positive results. The experience itself is real and can be striking; whether anything in fact leaves the body remains, from a scientific standpoint, unsupported, and the practice sits at the disputed boundary between spiritual technique and the study of unusual states of consciousness.