Dear Gould,

You did not mean to leave it in. The engineers tried — I have read this — they brought you in and played you the room mic and told you, plainly, that you were on the tape, that nothing short of recording the whole thing over could be done, and you went away and thought about it for a day and came back and said leave it. I cannot help it, you told them. The playing requires it.

The first time I noticed you under the music I thought it was a fault in my speakers. The second time I thought it was a leak from the next room. The third time I understood it was you, and I stopped trying to listen past it. Now I do not know how to listen without it.

You sing to yourself while you play because you cannot play without singing — because the line you are about to make with the hand is already in your throat first, half a breath ahead, the way it is for any of us when we are trying not to lose a thought. The hum is the thought outrunning the wrist. You spent your life apologizing for it and never stopped doing it, and the recordings would be worse without it — thinner, more polite, belonging to no one in particular.

I think about you sometimes with the lamp on at five in the morning, when the kettle is on its second go and the line I am after is still half a breath ahead of me. You would not approve of being remembered for the humming, or of the lamp either; you would have preferred a colder room. Still — the man who keeps making the sound he is trying not to make is the man who is going to be honest on the page, and the same is true of you on the keys, and I owe you a letter for it.