Harmony of jazz and related forms of music – music that originated from the fusion of European and African musical cultures on the American continent – is a very complex subject. Significant for these forms of music is the culture of improvisation and interpretation. A melodic theme, created by the composer with a limited harmonic structure and annotated with only a few chord symbols, has to be re-created into a complete musical product by the performing musician or arranger (in this book both joined in the pianist), based on his own interpretation, and – very important – without affecting the specific character of style nor straining the ideas of the composer. This requires knowledge and insight, and a huge dose of creativity and musicality as well. This method is designed to make a complex but very interesting subject accessible in a very practical way. It is aimed at those who, on account of study, profession or pure interest, want to improve their knowledge and skills of harmony and chords in jazz and related forms of music. The author has opted for a methodical, constructive, and from the perspective of performance very practical approach. Only when needed for a better understanding, some theoretical support is included. The many examples in the book are a source of information. The exercises guarantee a solid training, but will also invite the performer to make fascinating and inspiring discoveries, thus challenging his creativity and further development.