“I have never started a poem whose end I knew,” Robert Frost said, because “writing a poem is discovering.” But how do writers know when they’ve discovered the end? How do we know when a piece of writing is done, is the way we want it, the way it must be? Perhaps that’s why the Internet teems with advice for poets seeking counsel and support for dealing with this problem. I recall a thread that had the caption, “How the hell do I end a poem?” The post Beginning and Ending: Lou...