This new musical theory comes in the original form of an alphabet with notches. A sort of little theoretical dictionary to quickly find a forgotten notion. In addition, the number of concepts makes it possible to adopt a logical progression either in chapters or by means of a curriculum per year of teaching throughout the first cycle. Each concept, presented on one page, offers two levels of reading, depending on what you want to teach students: large print, the definition to learn by heart if necessary, in small print, clarifications and extensions possible for a deepening. A musical example from the repertoire always illustrates the definitions, and very often blank staves complete the page for the student to write another example that he has found himself.