It's about a little boy who does not now what a cavity is. When his mother tells him it is a tooth with a hole, he opens up his dog's mouth to see if his dog has a cavity. He discovers that his parrot does not have any teeth. This book has many, many animals showing what kind of teeth they have. You have to read this book to find out how Tim finds out what a cavity looks like. It is a fun and educational book for young childen, Children will love the many animals in this book