The role of a pianist accompanying a singer is clear: provide what is needed, essential, nothing more. These performances should not be biographical portraits of the keyboardist; thus, listeners following Ida Cox along on her "Rambling Blues" would have no idea that pianist Jesse Crump had been an organist in churches, theaters, and vaudeville houses or had performed on stages himself as a singer, comedian, and dancer. Crump later got into playing classic jazz on the West Coast with bandleaders such as Marty Marsala and Bob Scobey. Odd details only slightly blur the picture of...