The history of meridian tapping began with Dr. George Goodheart, a leading chiropractor and Applied Kinesiologist who found he could use acupuncture points beneficially for physical conditions by just "tapping" on them (no needles were needed!)
An Australian psychiatrist and Applied Kinesiologist, John Diamond, M.D., then took this discovery a step further. He began using verbal affirmations as the patient was stimulating the acupuncture points. This was a major step forward as it introduced a psychological tool into the process. But still the treatment method lacked a cohesive "engine" to drive it forward with real effectiveness. That engine was supplied by Dr. Roger Callahan, an American psychologist and Applied Kinesiologist specializing in anxiety disorders.
Dr. Callahan's contribution was immense and has been well documented. Through his interest in acupuncture and his awareness of the use of the value of tapping on acupoints, he made a key discovery upon which all later meridian tapping methods are based. Callahan found that if a person is focusing on a specific fear at the time they tap, that fear can be removed, often permanently. He developed his discovery into a complete system and concluded that there was a correct tapping sequence for every emotional issue, and that this could be determined for each individual through the use of muscle testing. He called these tapping sequences "algorithms" and his treatment later became known as Thought Field Therapy, or TFT.
The next step was the creation of simplified versions of Callahan's technique. These were known as "single algorithm techniques" (i.e. they did not require diagnosis or muscle testing). Then, in the 1990's, one of Roger Callahan's pupils, Gary Craig, unveiled a major development of the meridian tapping techniques which he called Emotional Freedom Techniques (EFT).