Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A "must read" for any mountain biker

Mastering Mountain Biking Skills in not only the best mountain biking book I've seen, its one of the best sports training books that I've ever seen. It has tons of photos to illustrate every skill that the authors are trying to teach. It seems like a lot of love of the sport went into both the writing and making of this book - it seems like the authors really want thier readers to become the best MTB rides that they can. You will see all of the skills and techniques needed to become a great MTB rider.