Life as we Knew It is a really good book. It has an apocalyptic aspect, and it provides a very unreal situation. If the moon was knocked out of orbit, it would continue to go towards Earth, and eventually smash into it. The logic in this is very flawed with the moon, and the way everything happens. Not everyone's going to grab their favorite food, people will go for the canned goods too.
This book isn't very realistic. I mean it could happen, but the asteroid would have to be half the size of the moon to even get the moon to turn. I really can say, though, that the way this book was put together, and the way the characters interacted with one another, that it was good. I recommend this book.