Forget trying to sell your book, this author says. Just seduce the agent.
I like that approach. Without it, writer's are focused on the wrong things and can get frustrated trying to pack their 400-page novel into one paragraph of a 1-page letter.
Just prove that you're professional, intriguing, and can tell a story. Don't try to dump your story on their desks via query. Make them crave it through the tease.