EFT is a kind of emotional acupuncture.   Just like acupuncture, it works directly on the meridian system in the body, but instead of needles, you stimulate the major meridian points by tapping on them or massaging them lightly while focussing on the pain or problem at the same time.  It is part of a genre of therapies that link psychological and physiological distress with disturbances or blockages in the subtle energy field in the body (known as chi in the Chinese system or prana in the Indian Yoga system). It was discovered when a clinical psychologist, Roger Callahan, after months of fruitlessly trying to treat Mary, a patient with a long-standing, severe water phobia had a sudden inspiration.  Drawing upon his knowledge of Chinese medicine and the theory of the meridians of energy flows, he asked her to tap on an acupressure point under the eye while thinking of her phobia.  Marys anxiety had tended to be located primarily in the sensations of her stomach, and Callahan knew that the point under the eye was the location of an end of the stomach meridian.  After two minutes of tapping, Mary declared, in amazement, that the phobia had gone.  Two decades later Mary is still free of her phobia.  One of Callahans students, Gary Craig, designed a universal tapping sequence that could be applied to more or less any psychological problem and he termed this technique EFT.  The common belief is that a negative emotion is the direct result of a traumatic or negative event, or memory.  This would suggest that all negative emotions manifest in a simple cause/effect way.  However, energy based therapies like EFT offer an alternative viewpoint:  The cause of ALL negative emotions is a disruption in the bodys energy system, which then leads to a negative emotion.  Therefore, rather than attempting to undo the thoughts or memories, EFT targets and resolves the disturbance in the energy field.  EFT does not change the memory itself, that remains the same, what EFT does is to change the way you feel about it.  This means that traumatic events can be recalled without the trauma, they become.... just something that happened. 

EFT is a self help protocol, designed for ease of use and so everyone can benefit from Emotional Freedom Techniques without prior knowledge about meridians.  It provides rapid relief from a vast array of emotional and physical states and there is now considerable evidence of the efficacy of EFT most particularly with anxiety related problems.