Cautionary note: This book series was originally intended to be read to children in those precious bonding years of four and five year olds. But the books slowly and gradually become more elaborate, using harder words. This encourages a better learning experience, as you the reader get to explain certain words or phrases to them.
As the series progresses, the books become funnier, but also scarier. At many school readings, the children always seem to want me to read the scarier books. Although the monsters and pictures become scarier, they are no more scary than a Disney movie. So before you read to a young one, please flip to the end, to see if the scary monsters are too harsh for more sensitive viewers. These books will also serve to teach and delight early readers.