Instruct: Classify Amazon reviews into positive or negative sentiment
Query: I believe I made the best investment ever!

I was still in High School when I bought this book. I thought it could help me somehow with my finals, but I mostly bought it cause after skim reading it in the bookstore, I knew I was gonna need it later on. Surprisingly, it did help on my finals as well. Most of the theory we had to study (apart from proofs of course) was concentrated in a few pages each, so it was easy for me to learn the stuff I really had to remember from there! Later in the summer I read it more carefully, and saw that it was indeed gonna be a big help for my later-on college years! It's condensed, thorough, thus making a great reference guide for everything a college/university student (to give an example) will need!