Instruct: Classify Amazon reviews into positive or negative sentiment
Query: completely outdated

Not only is the information old, it's not very comprehensive. If you can get hold of Ron Falcone's Complete Guide To Alternative Cancer Therapies (also outdated but technically, very informative and provides an excellent background into key alternative therapies), do so. From a historical standpoint, Falcone's work is an excellent and scholarly introduction to the subject.