Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Double selling

I am very fascinated by the books of all the 3 writers. Unfortunately only after I bought it I found out that this were only excerpts from older books . In the meantime I noticed that apparently this is common for there 3 writers to repackage same contents again and again. It's unfortunate as their books are so good. So please check the contents of their books before you buy them to save you some disappointment.