Keys and Chords answers two questions... What is a key? and, What chords are in the key? You could memorize a french dictionary and still not be able to speak french. Likewise, you could memorize a chord book and still not be able to play guitar. We don't speak or play in alphabetical order This book will also introduce you to a numbering system that many studio musicians use in recording sessions. This numbering system (not math ) will help you develop your ear to recognize chord progressions.