The fact that I can hear this come from my crappy laptop speakers almost a century after it was recorded on some now-ancient machine makes me so very thankful but so sad at the same time. To hear this in person would be unbelievable.
I know that this may be subjective, but I have to think that Tatum was the greatest piano player/keyboardist in the history of the instrument. I am almost certain that Chopin, Liszt, Beethoven, and all the other great composers would have been in awe of his playing and imagination.
After hearing this i understand why a very young Oscar Peterson, in his own words got intimidated by Art Tatum talent and he stopped playing his piano for a few days after hearing Tatum for first time: he tought it was two people playing piano.