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:
This book is a highly cereberal study of history. I you want a lot of action look somewhere else. (I suggest David Drake or S.M. Sterling) If you want something to ponder this is the book. Asimov's ideas have been borrowed by other works so some of it will not seem new. The science is somewhat dated (nucleur light bulbs and economical transmutation). This book does give an excellent veiw of the forces of history. If you want to understand what causes nations to fall read this book. Just don't expect Star Wars style entertaiment.
Answer:
Positive