Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Extremely useful book!

I would give this book 20 stars if I could. I have bought it at least 10 times to give to others. I am a therapist and it was helpful in my own life. It discusses what boundaries are, how they develop, boundary problems, and how the lack of boundaries can cause chaos in one's life. It also discusses boundaries in specific areas - such as between you and your family, etc. It is an amazing book, and I will continue to recommend it to others. A true gem!