The Mills Brothers were an American jazz and pop vocal quartet of the 20th century who made more than 2,000 recordings that combined sold more than 50 million copies, and garnered at least three dozen gold records. The Mills Brothers were inducted into The Vocal Group Hall of Fame in 1998.
Their early recordings are characterized by their vocal ability to imitate other instruments. Advertisement copy billed them as "No musical instruments or mechanical devices used on this recording other than one guitar".
The Mills Brothers were actually biological brothers until John Jr. passed away in 1936 and was replaced by the father, John Sr, who would sing on "Caravan" in 1940. The song "Out for No Good" is a duet with Dick Powell.