Instruct: Classify Amazon reviews into positive or negative sentiment
Query: DO NOT buy this book used

The only thing you buy this book for is the passcode for the online section of the "Universe" textbook. A used code that has already been activated will be worthless to you. This book just has an overview of each chapter, it contains no useful information other than the passcode. Its just another way publishers are riping us off. I wasted eight bucks buying a used copy.