We are ALL beings of energy:
To understand how Reiki, or any other form of energetic healing works, you must first understand that we live in a universe that is made up entirely of energy. Einstein, one of the greatest thinkers in the history of our planet, even put this principal into one of the most widely known mathematical equations; E=mc2 (Energy=mass times the speed of light squared) Everything in this universe is energy. Our thoughts are energy, our emotions are energy, even our physical bodies and all physical matter is just a dense form of energy.
Now that we understand we are beings of energy, we must realize that there is much more to us than just our physical bodies. Most of us have heard of the "aura", also known as the EMF (Electro Magnetic Field) or Bio-field, the energy field which surrounds the body and all matter. Most people, however, assume that the field radiates out from and is created by the body or object the field is surrounding, when in fact the opposite is true. It is the energy field that gives rise to the physical object, be it a chair or a person. It is the field which creates us and is this field that stores the bulk of who we are. Our thoughts, emotions, our past, the very essence of who we are resides in this field. Or more accurately in these fields, for there is more than one. Just as the physical body has different layers that perform different functions, so has the Bio-field.
We must also understand that the field not only creates us but it is this field that sustains us through our existence. It is through this field that we get the majority of the life force energy that we need to survive and stay healthy. Most people believe that we get the energy we need to survive from what we eat, drink, and breathe. Actually these provide us with only a fraction of the energy we need to survive. In fact in today's world it would be more correct to say we survive in spite of what we eat, drink, and breathe! The vast majority is attained from the sea of energy in which we live and filtered down through the various layers of the energy system before finally reaching the physical body. People can, and have, survived for weeks without eating, days without water, and minutes without air, but if we are cut off from the flow of life force energy into us, even for a second, we cease to exist.