What is Reiki?
Reiki means "universal energy" or "heavenly energy". (Ki is the Japanese word for the vital power that the Chinese call qi.) It is a spiritual practice and a form of "energy healing", somewhat related to qi gong, where concentration, visualization, and light static touch are used to help the recipient experience a healing transformation.
While reiki is a spiritual practice, by this we don't mean anything supernatural; the idea of spirit, or shen, is a central part of Chinese medicine. You don't have to have any specific belief to receive or practice reiki. While some writers and practitioners like to link reiki to various "New Age" concepts, in my experience and opinion this is not necessary. Reiki is a manifestation of the principle that "shen (mind/spirit) leads qi (vital energy)". Anyone who has ever given a comforting hug or touch has already practiced the essential principle of reiki.
Reiki can easily be combined with shiatsu, acupressure, or massage, or used on its own. It is especially useful for emotional balancing and for work on injured areas where massage or shiatsu would be contraindicated.