If I didn’t know it before, I know it now – Tolkien’s life was devoted to not only writing fantasy but to the study of fantasy as well. Leaf by Niggle is a short story about a painter, Niggle, who starts out painting a leaf that turns into a tree that is part of a forest and eventually becomes an entire country. Leaf by Niggle is brought together with the essay On Fairy Stories and poem Mythopoeia in this book titled Tree and Leaf.
This process is very much the same way Tolkien views fantasy writing. According to Tolkien and the painter Niggle in the short story, the most miniscule detail, such as that of a leaf, is as important as the whole piece. This can be seen in Tolkien’s fantasies as the origins of all his characters and creatures are given, even if he has to create them himself. He learned from his mistakes in The Hobbit and developed a more refined fantasy in Lord of the Rings.
In Leaf by Niggle, Tolkien suggests that writing fantasy cannot be forced. Some days it will be easier than others; at times, you may even have to leave a piece unfinished; you may not always have the end in mind but it will get developed as other parts get developed; you may even combine pieces from the outside to fit the whole. All of these points which Tolkien considers good fantasy writing is more clearly written in his non-fictional essay On Fairy-stories.