Music is a language. As a language it can be used to relate stories, called 'pieces of music'. In order to invent such a story, or, in other words, to create a piece of music, you should have some knowledge of the language's grammar. Most creative musicians, called 'composers', write their stories, or pieces of music, down on paper. Other musicians relate these stories by reading them from note sheets, simultaneously interpreting them with their instruments. They can do so without necessarily having any knowledge of the grammar that rules the language of music. Some creative musicians, called 'improvisers', relate their stories without reading them from note sheets, in a free, personal, spontaneous way. Surprisingly, they often do not seem to have much knowledge about the language's grammar either, or else do not seem to be able to use it in the same free, spontaneous way, which is apparently the reason why the vast majority of the listeners of music do not listen to them. This book has been written with the intention to contribute to changing this situation and to explore in greater depth the grammar that rules the language of music.