Instruct: Classify Amazon reviews into positive or negative sentiment
Query: How to throw your money out

I've been studying classical piano for 3 years and now I intended to learn something on how to improvise (to practice in contemporary music). So, why not buy a book called "Improvisation", right? Wrong! This book was my worst buy in Amazon! It says no word on how to learn improvising, there's not even one exemple or something like that. If all you want is historical data on important musician (including photos), then this book is for you. But, if all you want is ideas, clues, tricks on how to start or learn improvising, get away from it.