I said I would talk a little more about query letters. It's mainly a snapshot of your story with all the highlights in it and not much more than three paragraphs. (I'm talking about pitching freelance stories to publications, not book proposals, although there are some similarities as you read in Nicholas Sparks' letter.) Every sentence should be interesting and make the reader want to learn more. Think of it as the book jacket to your article. Or the subheads to your magazine piece. If you need more information, read this.
I'm preparing a query right now. I guess I needed time to talk myself into it, but I think I'm finally ready to submit (ooo! that sounded naughty!) Good luck to me! And good luck to you!