The towering thirty Goldberg Variations combine into a masterwork of keyboard music. As all variation pieces, they were based on a relatively simple source material. But as is his way, Bach organized the variations with a complex and deliberate structure. But also unlike other composers of this form, he poured more into this source material itself.  The famous Aria could stand alone as a sublimely decorated Baroque keyboard piece, but it doesn't stand alone; its bass line and harmonic progression (not its gorgeous melody!) are the actual foundations of all thirty variations. Bach simply could not resist pouring this beauty into even this, the harmonic "template" for the next 90 minutes of music! And this foundation does hold up, all the way until the end, where we are told to play the Aria again, now as our ending. Baroque ornamentation and performance practice takes this piece past its simple structure. We discuss this ornamentation and one particularly strange and almost inscrutable moment in the middle.  Aria mit 30 Veränderungen ("Goldberg Variations") BWV 988, as performed by Jean Rondeau for the Netherlands Bach Society