It's not a book I'm recommending this time, but a beautifully-written set of truths about writing.*
A few of my favorite lines:
"At any point in history there is a great tide of writers of similar tone,
they wash in, they wash out, the strange starfish stay behind, and the conches.
Emily Bronte was nine feet tall and had wings but everyone in that Victorian era was too proper to mention it ...
I get to use the word turquoise or melting or supernova right now if I want."