Instruct: Classify a given review as either positive or negative.
Query: this book has no backup

do not buy this book please!!! I thought it looked great and I have read a lot of blackjack books, and I can say out of about 20 this one is the worst. please stick to the basic books, anything by wong, or KO blackjack, blackbelt in blackjack, or anything by a respectable author. If you want to hear someone yammer on about the different places to eat in las vegas, this is your book. his system isn't backed up by any mathmatical facts AT ALL. he just boasts a 1% edge, without explaining, graphing or showing at all how he arrives at this. USE THIS BOOK FOR TOILET PAPER.