Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Save your money ... this book is not useful.

I purchase about three marketing books each month on Amazon. If I get one good idea, the money is well spent. I have a degree in PR with a marketing minor. I have studied marketing for 20 years and have over 200 marketing books in my library.This books ... sucks. There is really no other way to say it.The assertions are not researched based, some of the ideas are taken from other books, and some of the ideas are out-dated.