“With every sentence you write, you have learned something. It has stretched your understanding. I know that. Even if I knew for certain that I would never have anything published again, [or] would never make another cent from it, I would keep on writing.” – Brenda Ueland, If You Want to Write
NOTE: This was one of the books I read early in my writing journey, and found it inspiring. As of this writing the Kindle version is just 49¢.