I recommended this book for third grade and up because I believe the information presented is so clear and understandable.  Kathy Allen gives suggestions of how, when, and why to use your cellphone and also gives examples of consequences for not following those suggestions.  Opportunities are given for discussions of what is the right thing to do in a given situation, as well as safety precautions to take.    Anybody new to a cellphone will benefit from reading this book.