IMPORTANT!!! This sheet music book is necessary guidebook for every musician and mainly for piano and other keyboard instrument players! This already second edition of the title shows that it has been very succesful. Every musician who plays according to chord marks or tryes to improvise needs to know all these marks and scales. This sheet music book is very precise and will guide you not only through the world of scales and chord marks marking, but also will show you 12 most frequently used chords from each tone including all of their turn-overs (total of 540 chords) in a very objective way. Each chord is shown in a G clef, F clef, keyboard tone lay-out and in its most frequent indication. Very, very, very helpful title!!!