Five Children and It by E. Nesbit

This book tells the story of five brothers and sisters who discover a sand fairy while their parents are out of town. They make wishes and find that their wishes don't lead to the results they suspect--but while the story does have moral overtones, I didn't find it overly preachy. I particularly liked the wishes concerning their baby brother, Lamb, who was perhaps the most endearing and memorable character of the series. I think this is another one I would have loved if I had come to it a little earlier.