Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not bad for its purpose.

This book's strength is mainly as a reference text containing a lot of methods. As a textbook, the level of mathematical rigor may be too little to satisfy math majors and yet too much for physics and engineering students to deal with. Nonetheless (an older edition of) this book has been on my shelf for almost 25 years, and I still refer to it now and then.