Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Spend a few dollars more and get a better book.

This book is useful neither for review nor for learning from scratch. It seems to me that the only student who would benefit from this book is someone who knows precalculus so well already that he/she wouldn't need it. There are several other precalculus guides costing just a few dollars more that are much more helpful, and are of better quality to boot. (Some pages in this book just look downright amateurish, designwise). Do yourself a favor and skip this one; it's money wasted. I'm using my copy as a doorstop.