Instruct: Classify Amazon reviews into positive or negative sentiment
Query: very important book

This is a really great book, although it probably can only be appreciated by a chess player. There are a few books about chess that can be read as history or biography, this is NOT one of those. It is an encyclopedia of everything chess. Neither is it a chess tutor to make you a master player, but it will increase your enjoyment of the game. I keep my copy handy in my office. I have read it cover to cover and have read some of the entries many times. I believe that it is also scarce and often bringing a premium price, so I suggest that you get a copy if you can.