Ken Townsend is a renowned sound engineer who played an important role at Abbey Road Studios. He worked on several Beatles albums, such as "Rubber Soul", "Revolver" and "Sgt. Pepper's Lonely Hearts Club Band". In 1966 he invented automatic double tracking (ADT). Wikipedia
The definitive Wikipedia entry for Ken Townshend. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Ken_Townshend