According to Wikipedia;
Ralph Bass (May 1, 1911 – March 5, 1997), born in The Bronx, New York, was an influential Jewish American rhythm and blues (R&B) record producer and talent scout for several independent labels and was responsible for many hit records. He was a pioneer in bringing black music into the American mainstream. During his long career he worked for such labels as Black & White Records, Savoy Records, King Records, Federal Records and Chess Records, recording some of the greatest performers in black music, including Etta James, Sam Cooke, James Brown, Earl Bostic and groups such as The Platters and The Dominoes. By doing so, he was instrumental in helping to shape their careers. He was inducted into the Rock and Roll Hall of Fame in 1991 as a non performer, as well as the Blues Hall of Fame.
In the 1940s at Black and White Records Bass got his start as an A&R man. He produced and recorded, among others, Lena Horne, Roosevelt Sykes, Jack McVea (suggesting he record the hug hit "Open the Door, Richard") and T-Bone Walker, including T-Bone's landmark "Call It Stormy Monday".
In 1959, the Chess brothers hired Bass away from King Records in Cincinnati to serve as A&R Director at Chess Records. He was there until 1976, working with blues, gospel, R&B, and rock and roll artists, including Clara Ward, the Soul Stirrers, Etta James, Howlin' Wolf, Muddy Waters and Sonny Boy Williamson. Later, for MCA Records he produced John Lee Hooker.