If you had a choice, whether you could have all the literature in the world that exists, or just this one book, i would say, play. Kids love to play. They are close to their own nature. There is a reason why they love to play,. You could be sitting at dinner with them and something happens with the serving fork, and that's a game. By the way, animals love to play, too. Could play all day and day. Catch the ball, fetch the ball, run, chase the rabbit. Wouldn't know what to do with it if it caught it, but just wants to chase it and have fun. It's a game we love to play