Which Tolkien story features the artist named Niggle?

Tolkien’s story featuring the artist named Niggle is Leaf by Niggle.

First published in 1945, the story follows Niggle, a painter who becomes absorbed in creating a vast tree and landscape on a single canvas. He is repeatedly distracted by practical demands and by concern for his neighbor Parish. The tale combines fantasy, moral reflection, and Tolkien’s ideas about artistic creation.

The story is often read as partly autobiographical, though it is not a straightforward account of Tolkien’s life. Niggle’s unfinished painting has encouraged comparisons with Tolkien’s own immense, evolving mythology and his frustration with unfinished manuscripts. Leaf by Niggle later appeared in collections including Tree and Leaf. Its compact form makes it very different from The Hobbit and The Lord of the Rings, but it remains one of Tolkien’s best-known shorter works.