Instruct: Classify a given Amazon review as either positive or negative.
Query: Espresso - Crema of Coffee

Great book about espresso. One may wonder how a small cup half full of a black fluid with a little bit of froth on the top should be the sole subject of a whole book. After reading it is clear that espresso is more than just coffee. The book has the complete history of how espresso was invented, the history of the machines and every thing you need to know to get a good cup with the magic crema. It also describes the complete process about the bean's travel from the tree to the cup including treatment of the raw beans, roasting, grinding and brewing. It will also advise you on how to select your own equipment and that is where it is a little to limited. Kenneth Davids knows probably everything which is worth knowing about the subject but I missed some guidance to select a machine if you want to go further and invest into semi professional or professional brewing hardware.