Given reviews from Amazon, classify those review based on their content into two classes: Negative or Positive.

Let me give you an example: I've read this book with much expectation, it was very boring all through out the book
The answer to this example can be: Negative
Here is why: Review writer does not like the book because it was boring, therefore it is a negative review.

OK. solve this:
Going to be brief here: If you are looking for an introductory to economics, begin your search elsewhere. Hazlitt has an opinion, and he presents it here. I was looking for something that presents both sides of sticky issues, but more importantly, spends a great deal of time on the fundamentals.This book fails in that respect. Keep looking. (Samuelson, Mankiw, Malkiel...)
Answer:
Negative