During his 17 months on Sun Records, Elvis Presley changed himself and the whole world utterly. He entered the studio in 1954 as a withdrawn teenager with blonde hair, pimples, and an almost debilitating shyness. When he signed with RCA in 1956, he was a seasoned live act renowned for his energetic performances and a recording artist who confidently blurred the lines between country and r&b. His skin had cleared up, he started dying his hair jet…