"The Lost Beautifulness" is the story of a woman, Hanneh Hayyeh, who decides to paint her kitchen, in the poor rundown tenement where she and her husband live, to prepare for the homecoming of her son from the armed services during the war.
Everything that Hanneh does is with the idea of making her home beautiful for her son, who is her joy. To accomplish such a feat of fixing up her kitchen, she takes in extra laundry to buy the paint, and then does the work herself. It is a long time in coming as she can only save pennies at a time. However, when she is done, all but her husband agree that something beautiful has come out of her heart and transformed her kitchen into a wonderful, welcoming place; and everyone wishes her well for the good fortune of a beautiful room in her home.
When her landlord sees what she has done, he demands more money. The beauty of the room simply (in his eyes) makes the flat (apartment) worth more money in rent to him: if she cannot pay it, someone else will. (He raises the rent twice.)
Sadly, Hanneh tries to fight the landlord, to make more money: to fight the injustice where there should be fairness in this "land of democracy." She is, however, beaten, and she destroys the beauty of the kitchen, believing that if she cannot live there, she will not give the landlord the benefit of having the beautiful kitchen to rent out.
As she does this, the destruction hurts her more than anyone, and she is broken inside. She cannot, afterwards, understand what rage made her do such a thing. The beauty of the room had come from her heart, and it was almost like a living thing for the life she put into it. Destroying it robs her heart of the joy she had in creating it.
In terms of theme, I would say there are several. First, life is not fair.
Second, beauty should be free, to be appreciated and be a reward in itself, but some people cannot see beauty for its own sake—they must try to own it, robbing others of the ability to enjoy it. (In some ways, this is what happened when the Europeans arrived in the New World and "took" the land from the Native Americans. It was beautiful and rich, but they wanted it and took it for their own good.)
Third, beauty comes from the soul, but some people cannot see beauty in the world. Their eyes remain blind to what sits before them. For some of these people, things only have value if there is a reward involved; beauty should be its own reward, but some people miss the point completely.
Perhaps, too, the story is an allegory for how we try to create a world of beauty around us, but become so caught up in the wrong things (running around and doing so much), that we fail to slow down long enough to enjoy the beauty around us.