More than 37,000 harmonic progressions. Tool for musical composition and grids harmonization. This book aims to be a tool for composition, arrangement and harmonization. It is only an aid, no method can replace the trained ear of a Musician. However, the complexity of some harmonic progressions (Giant Steps, for example) shows that a little help would be helpful and that, faced with an extremely rich harmonic universe, there is an eternity of discoveries.