Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great Book!

I have played in various bands for 10 years as a drummer, and the guitar players could never explain to me what constituted the "key" of a song or how scales and chords related to each other! So much for all their collective music lessons(many). This book explains it all in quick and understandable terms. You will know what to play with what key and also the variations that are appropriate with each key/scales. Forget all the "learn how to play this song" books!