Instruct: Classify Amazon reviews into positive or negative sentiment
Query: very painful

The author seems to jump around subjects and I don't think his aim was clarity of explanation at all. I think his goal was to fit as many extra words and unrelated babbling as he could. The book was just way too much of everything and not at all focused. I don't know how else to explain this. It was a required read for a class and I would say that it was excruciatingly painful, hard to follow, and I got absolutely nothing for my time. I can't tell you a single thing that I got out of it.