It rained all day on Sunday. Big, booming thunderstorms struck down my internet service, effectively isolating me from the outside world. It was the perfect day to stay in sweatpants, grab a cozy blanket, and finally crack open Stephenie Meyer's Twilight. Or was it?I was already engrossed in the first chapter of the instantly addictive vampire romance saga when something caused me to look up from the page. My eyes coincidentally landed on James McAvoy staring off into the chaos of the evacuation of Dunkirk. It was the paperback copy of Ian McEwan's Atonement I'd picked up last year. I'd been eager to read it before going to see its highly praised film adaptation -- just like I'd recently bought a certain vampire novel whose highly anticipated movie opens December 12.I flashed back to the night I'd finished reading Atonement. It was the night before I had plans to see the movie, and I stayed up late to devour the final chapters. It was a great novel full of intricate details, painfully dark emotions, and a pair of lovers you couldn't help but root for. But as I turned the last page (don't worry, no real spoilers are ahead), one turn of a sentence changed the fates of every character. It was one of the most mind-blowing, emotionally shattering twist endings I'd ever read. And waiting for it to happen on film completely ruined my enjoyment of the movie the next night.I've always been a read-the-book-first kind of girl. On the other hand, I've always avoided movie spoilers like the plague. But Atonement was both a terrific read, and a vile movie spoiler. Twilight is the first book I've planned to read in order to prepare for a movie since that fiasco. And now I'm left in a classic chicken-or-the-egg type quandary: would I rather risk spoiling the book, or the movie?Although I'd hate to have another Atonement experience, I think my movie-going history has proven that reading the book first is usually a more rewarding experience. I'm always horrified when I hear people profess their fandom for the Harry Potter films and then tell me they've never read the books. It's a struggle for me not to immediately abduct these people and drag them to the nearest bookstore to remedy the situation. Instead, I have to settle for talking their ear off about how they're missing so much by not reading the books. Even the best Potter films don't come anywhere near capturing the magic and the danger of the world J.K. Rowling created. I know I never would've understood what all the hype was about if I'd seen Harry Potter and the Sorcerer's Stone without reading the book first. Even worse, based on the movie alone, I probably never would've picked up a Potter book at all. And I would've missed out on a pretty great piece of pop-culture history.The thing with movie adaptations of books is that while a few get it exactly right (Gone With the Wind, To Kill a Mockingbird, the Lord of the Rings trilogy to name a few), and every once in a while a filmmaker is even able to create a better piece of art than their source material (The Talented Mr. Ripley, The Devil Wears Prada), most are just trying to fix something that was never broken. While I'm hoping, for the sake of its frighteningly passionate fans, that Twilight will turn out to be a great movie, I won't truly get the chance to take in this phenomenon unless I read the book first. If Stephenie Meyer had envisioned Bella and Edward as movie characters, she would've written a screenplay. But she felt their story could best be told in a book, and that probably means reading the book is the best way to take the story in.I'll never get to go back in time and hold off on reading the last page of Atonement before seeing that twist unfold on the big screen. But if I had seen the movie first, I never would've learned how much impact one little sentence can have on an entire novel, and the entire lives of its characters. In the end, that was probably worth giving up some quality time with James McAvoy.