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:
Although I read this book many years ago I recall that it is a well-written and engaging examination of women's sexuality. The difficulties that many young women face as they mature into fully functioning sexual adults - as mitigated by their upbringings as well as the varied expectations of society and their partners - are nicely illustrated through a series of real life case studies. The author, Dr. Bardon, was a teaching and research member of the faculty of the University of Minnesota from the early 1960s through the late 1990s. Some of the book will undoubtedly be dated, but much of it is just as relevant -...- today as when it was written in the mid 1970s. As used copies are readily available through Amazon.com I highly recommend picking one up.
Answer:
Positive