Gladwell points out that there are two types (well, for our purposes) of genius: the Creators and the Tweakers.
The creators make huge innovations. Come up with things that have never been done before. The Tweakers, well, "tweak." Tweakers make the "micro inventions necessary to make macro inventions highly productive and remunerative." In other words, tweakers take the big bangs and, with a series of small, well-placed sparks, make a bigger one.
I think this is relevant to writing, in the sense that writers live in fear of not being original. Fearful of that old adage: "There are no new stories."
Gladwell points out, and I agree, that small innovations are as important as the earthshaking ones--can, in fact, be the earthshaking ones.
So write what you're writing, and don't worry that J.R.R Tolkein did it first. You're doing it different. Shoot, you might do it better. (Just don't tell me that in your query)