Stax Records is rightfully renowned for its catalogue of deep southern soul straight from the heart of Memphis.  But, like its famous Detroit competitor Motown, the label founded by Jim Stewart and Estelle Axton released music in a variety of sounds and styles.  The Complete Stax-Volt Singles 1959-1968 (released in 1991 and reissued by Rhino in 2016 was the first major archival box to begin to address the Stax legacy in record-by-record fashion.  It was followed by The Complete Stax-Volt Soul Singles, Vol. 2: 1968-1971 (1993, reissued 2014) and The Complete Stax-Volt…