Here's a very nicely produced, slightly oversized, slim paperback volume containing... yes, Marcel Proust's letters to his neighbor.  Translated by Lydia Davis, who has also provided plenty of introductory material, notes, and even a diagram of Proust's apartment so you can follow the action.

Here's publisher, New Directions' hype up:

Marcel Proust’s genius for illuminating pain is on spectacular display in this recently discovered trove of his correspondence, Letters to His Neighbor. Already suffering from noise within his cork-lined walls, Proust’s poor soul was not ready for the fresh hell of his new upstairs neighbor, Dr. Williams, a dentist with a thriving practice directly above his head.

Chiefly to Mme Williams, these ever-polite letters (often accompanied by flowers, books, or compliments) are frequently hilarious—Proust couches his pained frustration in gracious eloquence. In Lydia Davis’s hands, the digressive brilliance of his sentences shines: “Don’t speak of annoying neighbors, but of neighbors so charming (an association of words contradictory in principle since Montesquiou claims that most horrible of all are 1) neighbors 2) the smell of post offices) that they leave the constant tantalizing regret that one cannot take advantage of their neighborliness.”

Lydia Davis has written a generous translator’s note, tracing much of what we can know about Proust’s perpetually darkened room; she details the furnishings as well as the life he lived there: burning his powders, talking with friends, hiring musicians, and most of all, suffering. Letters to His Neighbor is richly illustrated with facsimile letters and photographs—catnip for lovers of Proust.

Madame,

I have been wanting for a long time to express to you my regret that the sudden arrival of my brother prevented me from writing to you during the last days of your stay in Paris, then my sadness at your leaving. But you have bequeathed to me so many workers and one Lady Terre—whom I do not dare call, rather, “Terrible” (since, when I get the workers to extend the afternoon a little in order to move things ahead without waking me too much, she commands them violently and perhaps sadistically to start banging at 7 o’clock in the morning above my head, in the room immediately above my bedroom, an order which they are forced to obey), that I have no strength to write and have had to give up going away. How right I was to be discreet when you wanted me to investigate whether the morning noise was coming from a sink. What was that compared to those hammers? “A shiver of water on moss” as Verlaine says of a song “that weeps only to please you.” In truth, I cannot be sure that the latter was whispered in order to please me. As they are redoing a shop next door I had with great difficulty got them not to begin work each day until after two o’clock. But this success has been destroyed since upstairs, much closer, they are beginning at 7 o’clock. I will add in order to be fair that your workers whom I do not have the honor of knowing (any more than the terrible lady) must be charming. Thus your painters (or your painter), unique within their kind and their guild, do not practice the Union of the Arts, do not sing! Generally a painter, a house painter especially, believes he must cultivate at the same time as the art of Giotto that of Reszké. This one is quiet while the electrician bangs. I hope that when you return you will not find yourself surrounded by anything less than the Sistine frescoes… I would so much like your voyage to do you good, I was so sad, so continually sad over your illness. If your charming son, innocent of the noise that is tormenting me, is with you, will you please convey all my best wishes to him and be so kind as to accept Madame my most respectful regards.

Marcel Proust