Atonement, published in 2001, is a book about screwing up.

It's by Ian McEwan—a serious and critically acclaimed big-deal novelist who won the Booker Prize, so when he writes about screwing up, you can be sure it's not your garden variety oops-I-washed-my-jeans-with-a-pen-in-the-pocket kind. The stakes are a whole lot higher—and by higher, we're talking falsely-accusing-your-sister's-boyfriend-of-a-horrible-crime-and-ruining-her-life higher. This is the kind of screw up that you don't come back from.

The screwer up here is Briony Tallis, a dreamy, upper-class 13-year-old control freak who we first meet in England before World War II. Briony wants to be a writer because—she figures—they get to control the whole world. When you write, after all, your characters do what they're told to and speak when spoken to. You can make up a character, give him an awful name like Beluga Throckmorton, and then make the poor guy do all of your homework. And you know what? He has to listen to you on account of living inside your brain and all. Dude's got no other choice.

Instead of putting Briony in control of the world, though, her imagination ends up spreading chaos and misery and guilt and zombie attacks. Okay, not zombie attacks—it's not really that kind of book. But on the other hand, Cecilia—the sister whose life Briony ruins by falsely accusing her boyfriend—does experience such intense romantic tragedy that she had to be played by Keira Knightley in the 2007 film adaptation. That's right: Keira is sad and it's all Briony's fault. No wonder she feels horrible. You would as well—and you deserve to after the horrible way you treated poor old Beluga.

Ian McEwan's Atonement is a novel that does a lot of thinking about novels. You can see why this would interest McEwan since he's a novelist and all. But many of you probably aren't planning to write novels. Many of you probably don't even want to write novels. So why should you care about Atonement?

The thing is… while many (okay, most) people don't necessarily write novels, everybody makes up stories. For instance, you might look at Atonement—all 300 pages of it—sitting there glaring at you, and imagine how someday you'll get to the last page and then toss it across the room or beat it with a stick or go have a candy bar. You might imagine what it would be like to win that soccer game you have tomorrow, or just to be done with the test you're studying for next week. Or maybe sometimes you might even imagine what it would be like to talk to a cute classmate you're a bit shy around (you know the one). These imaginings are your story, your novel, the one—to paraphrase McEwan—that is writing itself around you (1.13.27).

We tend to think of what we imagine as being stuck inside our head. What Briony finds in Atonement, though, is that what's in your head can get out and start walking around. Sometimes this is totally cool, but sometimes it's really, really bad. Let's say, for example, that your brain tells you that your history exam is next week, when in actuality it's this week. You might find yourself feeling pretty bummed, not to mention cross with your own brain. Or what if you decide that you have absolutely no chance of winning your soccer game this weekend? Well then you might not even try—and so the not winning of your imagination becomes a self-fulfilling prophecy in reality. Our imaginations don't only focus on ourselves, though. For instance, let's say you can't find your copy of Atonement anywhere. The friend you lent it to last weekend assures you that she put it back in your locker on Monday, but your little brain doesn't quite believe her so you decide to stop speaking to her. Whether you're right about the book or not, the inner-workings of your brain have just totally impacted the lives of both you and your friend.

Imagining doesn't always mess things up, though. Sometimes thinking about getting to know that cute classmate can lead to actually getting to know that cute classmate. And sometimes, too, you need imagination if you're going to fix the problems your brain has caused. How can you atone, or make up for, what you've done if you can't first imagine doing right?

Atonement, then, isn't just about big honking books. It's about the stories in our heads and how they get out and spread trouble—and occasionally good cheer—on their own. Atonement isn't just for novelists, but for anyone who has a head and has to live, one way or the other, with the things banging around inside it.