This book, through simple illustrations and very readable text, gives young children (approximately Kindergarten thru third grade) an excellent explanation of the moon and the changes we can easily observe in it during a month. What often seem like complex concepts - the phases of the moon and its movement relative to the earth - are made very understandable through the text and a very simple experiment involving an orange stuck onto a pencil (a styrofoam ball stuck onto a chopstick worked quite well for us with less mess) and a flashlight. Naturally, it's recommended to do some real observations along with the book.