Instruct: Classify a given review as either positive or negative.
Query: pocket book at a multi-volume price

This small volume is well organized and has a fair amount of useful information. The kicker (and it's a huge kicker) is the cost. The $50 price tag is absurd. The book is one of those things you'd expect to pick up for free at a scientific meeting or conference. If you're considering purchasing "Essentials" I'd suggest that you wait until you find a gratis copy, or perhaps a $10 copy from a reseller.