I bought this book for my four year old daaughter because we both loved Alphabet Adventure so much. The story centers on little x this time. He decidedes to run away because he is a letter that isnt used very much. All of the other letters embark on an adventure to bring him home. This book is especially perfect for this time of year. There is a spooky castle and a monster M that evokes images of Halloween. At the end of the story little x realizes that he is a very special letter after all. Children love the idea of a mystery and the illustrations in this book are really wonderful. Everytime you read it you will see something new. My daughter especially loves the page where the letters match up to an object that they begin with. My daughter has learned a lot from this book and Alphabet Adventure. I highly recommend them both.