Rock Harmonica Book/2-CD Set: Power Licks, High-End Licks & Speed Licks! by David Barrett. The blanket term 'rock' is used to describe a musical genre that covers over six decades of musical diversity. The question for this book is, "What does rock mean to harmonica players?" This book is for harmonica players who have a basic grasp of the instrument and are looking to study the rock style in greater detail. You'll learn greater control of bends; speed licks; high-end licks and more.