Paul Vaughn Butterfield was an American blues harmonica player, singer and bandleader. After early training as a classical flautist, he developed an interest in blues harmonica. He explored the blues scene in his native Chicago, where he met Muddy Waters and other blues greats, who provided encouragement and opportunities for him to join in jam sessions. He soon began performing with fellow blues enthusiasts Nick Gravenites and Elvin Bishop.

McKinley Morganfield, known professionally as Muddy Waters, was an American blues singer and musician who was an important figure in the post-World War II blues scene, and is often cited as the "father of modern Chicago blues". His style of playing has been described as "raining down Delta beatitude".