Original sentence: By this time Threadgill's place amongst the upper echelon of the avant-garde was secured, so prolific in fact that he was signed by Columbia Records for three albums (a rarity for musicians of his kind)
Edited sentence: By this time Threadgill's place amongst the upper echelon of the avant-garde was secured, so prolific in fact that he was signed by Columbia Records for three albums(a rarity for musicians of his kind).One of the albums made by this band, Too Much Sugar for a Dime, is often considered  a desert island disc by many fans of avant-garde music