Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Excellent coverage of a difficult topic

... this book is incredible. I have a degree in mathematics and the principles expressed are extremely sound -- but far more important than the formulas are the first couple of chapters which cause you to view trading in a very different, and statistical, manner. Although the theories in this book can really only be applied to a trading system (which I haven't really used), after reading this book over several times I understand that there is a mathematical certainty that I will eventually lose my trading capital if I don't start approaching trading in a more systematic fashion. Anyway, I highly recommend it -- the sections on gambling theory alone are worth buying it.