One that I treasure deeply is Jonathan Lethem's The Ecstasy of Influence which, amongst other things, is an assault on the idea of sui generis art that not only argues for redefining what originality is so that it's a creatively useful concept, but is an object lesson in how that new definition might work.
I've linked to it many times over the years, mainly to discuss its relationship to intellectual property, which is the essay's subject. But lurking within Lethem's entry into the Copyleft movement is an honest and generous discussion of how creativity actually works.
And did I mention the entire thing is available for free on the internet? I didn't. Oh. Sorry about that. Here it is.
We have a lot of wonderful, creative people reading this blog. What writing about creating do you draw inspiration from?