In the rock & roll era, the "A&R" job description usually implies a schmoozer whose musical talents, if any, lie in an instinct for commerce. While the latter skill was of obvious importance to record company executives in the '20s, some of them, such as Fred Hager, also had the type of creative abilities more often associated with performers themselves. While remaining behind the scenes, Hager was actually an adept pianist, arranger, and conductor. When he assembled a special group to back singer Mamie Smith in the early '20s, Hager may not have realized that he had just hit ...