This book is devoted to the forgotten chords from harmonic minor and harmonic major. As far as that goes, it is addressed to the advanced musician who already has the theoretical basis at his disposal. But in order to explore the area of harmonic minor and harmonic major, a closer examination of those scales and chords that precede the forgotten chords is required, i.e.: the church modes and the melodic minor system. In this concern, it is also useful for the beginner who first wants to get the general idea of jazz theory.