Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: A must read

Dr. Powers has been a major contributor to the understanding of autism spectrum disorders for many years. The ORIGINAL book was one of the few available on the subject at the time of publishing, and while it is NOW outdated, it has been replaced by the current edition published in 2000. This edition contains much useful information that parents will not find elsewhere. I was, therefore, somewhat confused that the reviews for the previous edition are still on this website, as they really describe a different book, which is very misleading.