Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great Book

I did not buy this book, I borrowed it from the local library.My son is working on the book. I can feel he is enjoying those puzzles. Level 1 and Level 2 seems not that difficult, but not level 5 puzzles, about half of them, hints are needed and still he might get the wrong answers. His USCF rating is about 1400.