Astral travel is a visionary process which is based on the idea that every human has an "astral body" or "body of light" which though closely associated with the physical body is separate from it.
In astral travel, the practitioner attempts to move his consciousness from his physical to his astral body and then to move his astral body outside of his physical body. This may occasionally be achieved spontaneously but usually follows a series of strong visualisations. Once inside the astral body, the practitioner is free to roam where he or she pleases. The practitioner may attempt to explore the physical universe in which case the process has been termed "aetheric travel" or may explore parallel universes (known as the astral plane) in which case the process is termed "astral travel". In practice there is often very little difference between the two. The quality and intensity of the experience may vary from a strongly imagined experience to a waking dream.
Astral travel is used for a number of purposes in Magick; the important, functional parts of rituals are said to take place "on the astral" and it is often useful to observe these taking place; visionary experience in ritual invariably takes place as a type of astral vision and travel within the astral plane with the purpose of discovering information about specific or general is a further use. There is quite a close relationship between astral travel and pathworking which, in the opinion of the present author, is a type of astral travel.