The elephant and piggie series has quite a few books. It's great entertainment for early readers or preschool aged kids. Although, I've read these books to fourth graders and gotten a great response too. They are clever and simple. It's magic!
This one is my daughters' all time favorite books. She memorized it when she was 3. I've had to buy several copies because she has loved this book a little too much.
I have all of Mo's books. He rocks! If you are looking for some fun books to explore with your kids or grand kids, give Mo a try. You can't go wrong.