J. R. R. Tolkien was a scholar of English literature, a philologist and medievalist interested in language and poetry from the Middle Ages, especially that of Anglo-Saxon England and Northern Europe.

His professional knowledge of works such as Beowulf shaped his fictional world of Middle-earth, including his high fantasy novel The Lord of the Rings.

However, mundane duties constantly prevent Niggle from giving his work the attention it deserves, so it remains incomplete and is not fully realised.

Back at the home to which he cannot return, Niggle's painting is abandoned, used to patch a damaged roof, and all but destroyed (except for the one perfect leaf of the story's title, which is placed in the local museum).

"[T 10] The Tolkien scholar and fellow-philologist Tom Shippey states categorically that the story is "quite certainly" an allegory, and that its first words recall "to any Anglo-Saxonist" the opening lines of the Old Northumbrian poem Bede's Death Song.

His time in the institution and subsequent discovery of his Tree represent purgatory and heaven; Sebastian Knowles writes that the story "follows Dante's 'Purgatorio' in its general structure and in its smallest detail.

[6][7] Tolkien was compulsive in his writing, his endless revisions, his desire for perfection in form and in the "reality" of his invented world, its languages, its chronologies, its existence.

This philosophy is evident in Tolkien's other works, especially The Silmarillion—one Vala, Morgoth, creates the Orc race as a foul mockery of the Elves.

[T 11][15] Tolkien stated in another letter that he then wrote it out "almost in a sitting and very nearly in the form in which it now appears", commenting that looking back at the story, he thought it "arose" from a combination of his love of trees and his concern that The Lord of the Rings would never be finished.

[T 12] Organ describes the birth of "Leaf by Niggle" as "a frenzy of activity" resembling the automatic writing "popularised by proponents of Dada and Surrealism" in the early 20th century.

[15] Organ comments that Tolkien may have resisted "what he saw as the morbidity of surrealism" in connection with his story, precisely because "Leaf by Niggle"'s message is so positive.

[15] Jeffrey MacLeod and Anna Smol write in Mythlore that while Tolkien defines sub-creation "in linguistic terms", he often links such verbal creation to visual images.

In his own life, Tolkien combined the writing of fiction with his artwork, while he defined imagination visually as the "mental power of image-making".