Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Excellent Guide to Understanding Human Behavior

This book was recommended to me by someone who knew I would be joining the police force (I'm not even a marketer). I have to say that what I learned in this book might just save my life out on the street. Understanding tactics and human behaviour is vital if you want to be a good cop (or a good ANYTHING for that matter). This book will teach you some stuff that will leave your head shaking. Pretty profound ideas and methods in here. I read it in one sitting and will probably read it several more times. One of the best books I've ever read.