Reiki (pronounced ray-key) is, in its simplest translation, universal life energy. It has also been referred to in other cultures as light, chi, prana, and spirit. It is the life force that exists in all things. The practice of Reiki is the art and science of channeling this universal life energy to promote spiritual, mental, and physical well-being. Reiki is not associated with any particular religion and can be used alongside any spiritual system.

As Reiki involves directing the natural flow of universal energy, it can best be likened to recharging a battery. When a battery's energy supply is low, it doesn't function well. By introducing a charge to it, it can once again run on its own. Reiki works much the same way. If you are suffering from an illness (physical, mental, or spiritual), your energy supply is lessened ; Reiki works to assist you in bringing your energy level back up to its natural flow, thereby enhancing your own natural healing powers. Reiki practitioners do not suffer from energy depletion, as they are trained to channel energy from the outside environment, not from their personal supply.