Blue Rock Records was a subsidiary of Mercury Records, and like their parent, based in Chicago between 1964 and 1969. Despite their name, they didn't release blues or rock, concentrating almost exclusively on soul music, with a fair number of the singles echoing Chi-town styles popularized by Curtis Mayfield and other local producers and writers. Highlights included a version of "Mustang Sally" by its author, Sir Mack Rice. The best known Blue Rock Records artist was Dee Dee Warwick.